Coherent (COHR) 424B3Prospectus supplement

Filed Pursuant to Rule 424(b)(3)
Registration No. 333-255547

To the shareholders of II-VI Incorporated and the stockholders of Coherent, Inc.

MERGER PROPOSED—YOUR VOTE IS VERY IMPORTANT

On behalf of the boards of directors of II-VI Incorporated (which we refer to as “II-VI”) and Coherent, Inc. (which we refer to as “Coherent”), we are pleased to enclose the accompanying joint proxy statement/prospectus relating to the proposed acquisition of Coherent by II-VI in a merger transaction. We are requesting that you take certain actions as a II-VI shareholder or a Coherent stockholder.

On March 25, 2021, II-VI, Coherent and Watson Merger Sub Inc., a newly formed wholly owned subsidiary of II-VI (which we refer to as “Merger Sub”), entered into an Agreement and Plan of Merger (which we refer to as the “merger agreement”).

Pursuant to the merger agreement, Merger Sub will merge with and into Coherent (which we refer to as the “merger”) on the terms and subject to the conditions of the merger agreement, with Coherent continuing as the surviving corporation and a wholly owned subsidiary of II-VI.

The proposed merger of II-VI and Coherent would create a uniquely strategic global leader capable of delivering to the market the most attractive combination of photonic solutions, compound semiconductors, as well as laser technology & systems. The combined company would benefit from significant market megatrends, with the main applications in communications, semiconductor capital equipment, and consumer electronics, including those that enable the Cloud, 5G wireless, 3D sensing and consumer displays. Moreover, the combined company will be in a better position to accelerate its growth in industrial, aerospace & defense, life sciences and laser additive manufacturing by utilizing its expertise in engineered materials imparting differentiated performance in compelling integrated solutions in lasers, optics and electronics. With its expanded capabilities, the combined company will be able to collaborate even more broadly across its customer base as the design-in leader of choice. In addition, with a common culture of innovation and a strong track record of merger integration, the combined company will be in a strong position to deliver significant value to all stakeholders, including both companies’ shareholders or stockholders (as applicable), customers, employees and business partners.

In the merger, Coherent stockholders will be entitled to receive $220.00 in cash (which we refer to as the “cash consideration”) and 0.91 of a share of II-VI common stock (together with the cash consideration, the “merger consideration”) for each share of Coherent common stock they own (and, if applicable, cash in lieu of fractional shares). Although the number of shares of II-VI common stock that Coherent stockholders will receive per share of Coherent common stock is fixed, the market value of the merger consideration will fluctuate with the market price of II-VI common stock and will not be known at the time Coherent stockholders vote on the merger. Based on the closing price of II-VI common stock on the Nasdaq Global Select Market (which we refer to as “Nasdaq”) on March 24, 2021, the last trading day before public announcement of the merger, of $67.26, the merger consideration represented approximately $281.21 in value for each share of Coherent common stock. Based on the closing price of II-VI common stock on Nasdaq on April 30, 2021 of $67.14, the merger consideration represented approximately $281.10 in value for each share of Coherent common stock. The value of the II-VI common stock at the time of completion of the merger could be greater than, less than or the same as the value of II-VI common stock on the date of the accompanying joint proxy statement/prospectus. We urge you to obtain current market quotations of II-VI common stock (trading symbol “IIVI”) and Coherent common stock (trading symbol “COHR”).

In connection with entering into the merger agreement, II-VI entered into an Amended and Restated Investment Agreement (which we refer to as the “investment agreement,” including as it may be amended from

time to time), dated as of March 30, 2021, with BCPE Watson (DE) SPV, LP, an affiliate of Bain Capital, LP (which we refer to as “BCPE” and, together with its successors and any respective affiliates thereof that become an investor party to the investment agreement, as the “investors”). On March 31, 2021, II-VI issued and sold to BCPE 75,000 shares of newly designated Series B-1 convertible preferred stock (which we refer to as “II-VI Series B-1 convertible preferred stock”) for an aggregate purchase price of $750.0 million pursuant to the investment agreement (which we refer to as the “initial investment”). In addition, pursuant to the investment agreement and subject to the terms and conditions set forth therein, the investors (i) committed to purchase 105,000 shares of II-VI’s newly designated Series B-2 convertible preferred stock (which we refer to as “II-VI Series B-2 convertible preferred stock” and, together with the II-VI Series B-1 convertible preferred stock, as the “II-VI Series B convertible preferred stock”) immediately prior to the closing of the merger for an aggregate purchase price of $1.05 billion and (ii) have the option to purchase up to 35,000 additional shares of II-VI Series B-2 convertible preferred stock immediately prior to the closing of the merger for an aggregate purchase price of up to $350.0 million. The issuance and sale of the II-VI Series B-2 convertible preferred stock pursuant to the investment agreement (which we refer to as the “subsequent investment” and, together with the initial investment, as the “equity financing”) is contingent upon the closing of the merger in accordance with the merger agreement and is subject to certain other closing conditions customary for transactions of this type. The terms of the II-VI Series B convertible preferred stock are set forth in the Statement with Respect to Shares, filed with the Pennsylvania Department of State Corporations Bureau and effective March 30, 2021.

Based on the number of shares of Coherent common stock outstanding and reserved for issuance as of April 30, 2021, II-VI expects to issue approximately 22.3 million shares of II-VI common stock to Coherent stockholders and certain equity holders in the aggregate in the merger, representing total aggregate consideration of approximately $6.9 billion in value, based on the closing price of II-VI common stock as on Nasdaq on April 30, 2021 of $67.14. Upon completion of the merger, we estimate that Coherent stockholders and holders of Coherent equity awards entitled to receive merger consideration as of immediately prior to the merger will collectively own approximately 15.0%, II-VI shareholders as of immediately prior to the merger (excluding as a result of the equity financing) will own approximately 70.7%, and the investors will own approximately 14.3% of the outstanding shares of common stock of the combined company (in each case, on an as-converted and fully diluted basis and without regard to the fact that immediately prior to the merger, certain holders may own both II-VI and Coherent stock).

II-VI and Coherent will each hold a special meeting of its shareholders or stockholders, respectively, in connection with the merger, and in the case of II-VI, in connection with the subsequent investment. II-VI shareholders will be asked to vote to approve the issuance of shares of II-VI common stock pursuant to the merger agreement in the amounts necessary to complete the merger, the issuance of II-VI Series B-2 convertible preferred stock in the subsequent investment pursuant to the investment agreement, and the issuance of shares of II-VI common stock upon any conversion of the II-VI Series B convertible preferred stock issued in the equity financing (which we refer to collectively as the “II-VI share issuance proposal”), which requires the affirmative vote of at least a majority of the votes cast by II-VI shareholders present at the II-VI special meeting, in person or by proxy, and to approve certain other matters related to the merger. Coherent stockholders will be asked to adopt the merger agreement (which we refer to as the “Coherent merger proposal”), which requires the approval of the holders of a majority of the outstanding shares of Coherent common stock entitled to vote on the proposal, and to approve certain other matters related to the merger.

The special meeting of Coherent stockholders will be held virtually via a live webcast at www.virtualshareholdermeeting.com/COHR2021SM on June 24, 2021, at 8:30 a.m., Pacific Time. The special meeting of II-VI shareholders will be held virtually via a live webcast at www.virtualshareholdermeeting.com/IIVI2021SM on June 24, 2021, at 11:30 a.m., Eastern Time. Information about these meetings and the merger is contained in this joint proxy statement/prospectus. In particular, see “Risk Factors” beginning on page 42 of the accompanying joint proxy statement/prospectus. We urge you to read the joint proxy statement/prospectus carefully and in its entirety.

Your vote is very important regardless of the number of shares of II-VI common stock or Coherent common stock that you own. The merger cannot be completed without the approval of the II-VI share issuance proposal by II-VI shareholders and the approval of the Coherent merger proposal by Coherent stockholders. Whether or not you plan to attend your special meeting, please vote as soon as possible to make sure that your shares are represented at the meeting.

Each of our boards of directors recommends that holders of common stock vote “FOR” each of the proposals to be considered at the respective meetings. We strongly support this combination of our companies and join our boards in their recommendations.

Dr. Vincent D. Mattera, Jr.		Andreas W. Mattes
Member of the Board and		Member of the Board,
Chief Executive Officer		Chief Executive Officer and President
II-VI Incorporated		Coherent, Inc.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued in connection with the merger or determined if this joint proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

The accompanying joint proxy statement/prospectus is dated May 6, 2021, and is first being mailed to II-VI shareholders and Coherent stockholders on or about May 10, 2021.

ADDITIONAL INFORMATION

The accompanying joint proxy statement/prospectus incorporates important business and financial information about II-VI and Coherent from other documents that are not included in or delivered with this joint proxy statement/prospectus. This information is available to you without charge upon your written or oral request. You can obtain the documents incorporated by reference in this joint proxy statement/prospectus through the Securities and Exchange Commission website at https://www.sec.gov or by requesting them in writing, by e-mail or by telephone at the appropriate address below:

You will not be charged for any of these documents that you request. To obtain timely delivery of these documents, you must request them no later than five business days before the date of the applicable special meeting. This means that II-VI shareholders requesting documents must do so by June 17, 2021 in order to receive them before the II-VI special meeting, and Coherent stockholders requesting documents must do so by June 17, 2021 in order to receive them before the Coherent special meeting.

No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this joint proxy statement/prospectus. This joint proxy statement/prospectus is dated May 6, 2021, and you should assume that the information in this joint proxy statement/prospectus is accurate only as of such date. You should assume that the information incorporated by reference into this joint proxy statement/prospectus is accurate as of the date of such incorporated document. Neither the mailing of this joint proxy statement/prospectus to II-VI shareholders or Coherent stockholders nor the issuance by II-VI of shares of II-VI common stock in connection with the merger or the issuance and sale of shares of II-VI Series B convertible preferred stock in connection with the equity financing will create any implication to the contrary.

The joint proxy statement/prospectus does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy, in any jurisdiction to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction. Except where the context otherwise indicates, information contained in, or incorporated by reference into, this joint proxy statement/prospectus regarding II-VI has been provided by II-VI, and information contained in, or incorporated by reference into, this document regarding Coherent has been provided by Coherent.

See “Where You Can Find More Information” beginning on page 245 of the accompanying joint proxy statement/prospectus for further information.

Notice of Special Meeting of Shareholders

To II-VI Shareholders:

On March 25, 2021, II-VI Incorporated (which we refer to as “II-VI”), Coherent, Inc. (which we refer to as “Coherent”) and Watson Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of II-VI (which we refer to as “Merger Sub”), entered into an Agreement and Plan of Merger (which we refer to as the “merger agreement,” including as it may be amended from time to time). Pursuant to the merger agreement, Merger Sub will merge with and into Coherent (which we refer to as the “merger”) on the terms and subject to the conditions of the merger agreement, with Coherent continuing as the surviving entity in the merger and a wholly owned subsidiary of II-VI. A copy of the merger agreement is attached as Annex A to the accompanying joint proxy statement/prospectus.

In connection with entering into the merger agreement, II-VI entered into an Amended and Restated Investment Agreement (which we refer to as the “investment agreement,” including as it may be amended from time to time, in accordance with its terms), dated as of March 30, 2021, with BCPE Watson (DE) SPV, LP, an affiliate of Bain Capital, LP (which we refer to as “BCPE” and together with its successors and any respective affiliates thereof that become an investor party to the investment agreement, as the “investors”). On March 31, 2021, II-VI issued and sold to BCPE 75,000 shares of newly designated II-VI Series B-1 convertible preferred stock (which we refer to as “II-VI Series B-1 convertible preferred stock”) for an aggregate purchase price of $750.0 million pursuant to the investment agreement (which we refer to as the “initial investment”). In addition, pursuant to the investment agreement and subject to the terms and conditions set forth therein, the investors (i) committed to purchase 105,000 shares of II-VI’s newly designated Series B-2 convertible preferred stock (which we refer to as “II-VI Series B-2 convertible preferred stock” and, together with the II-VI Series B-1 convertible preferred stock, the “II-VI Series B convertible preferred stock”) immediately prior to the closing of the merger for an aggregate purchase price of $1.05 billion and (ii) have the option to purchase up to 35,000 additional shares of II-VI Series B-2 convertible preferred stock immediately prior to the closing of the merger for an aggregate purchase price of up to $350.0 million. The issuance and sale of the II-VI Series B-2 convertible preferred stock pursuant to the investment agreement (which we refer to as the “subsequent investment” and, together with the initial investment, as the “equity financing”) is contingent upon the closing of the merger in accordance with the merger agreement and is subject to certain other closing conditions customary for transactions of this type. The terms of the II-VI Series B convertible preferred stock are set forth in a Statement with Respect to Shares, filed with the Pennsylvania Department of State Corporations Bureau and effective March 30, 2021 (which we refer to as the “statement with respect to shares”). A copy of each of the investment agreement and the statement with respect to shares is attached as Annex B and Annex C, respectively, to the accompanying joint proxy statement/prospectus.

NOTICE IS HEREBY GIVEN that a special meeting of II-VI shareholders (which we refer to as the “II-VI special meeting,” including any adjournments or postponements thereof) will be held virtually via a live webcast on June 24, 2021, at 11:30 a.m., Eastern Time.

In light of ongoing developments related to the COVID-19 pandemic, the II-VI special meeting will be held solely in a virtual meeting format via live webcast. You will be able to virtually attend and vote at the II-VI special meeting by visiting www.virtualshareholdermeeting.com/IIVI2021SM. We are pleased to notify you of and invite you to the II-VI special meeting.

At the II-VI special meeting you will be asked to vote on the following matters:

The board of directors of II-VI has fixed the close of business on May 17, 2021 as the record date for the II-VI special meeting. Only holders of record of II-VI common stock as of the close of business on the record date for the II-VI special meeting are entitled to notice of, and to vote at, the II-VI special meeting or any adjournment or postponement thereof.

Your vote is very important regardless of the number of shares of II-VI common stock that you own. The merger cannot be completed without the approval of the II-VI share issuance proposal by II-VI shareholders.

II-VI’s board of directors recommends that holders of common stock vote “FOR” each of the proposals to be considered at the II-VI special meeting.

Whether or not you plan to attend the II-VI special meeting, we urge you to please promptly complete, sign, date and return the accompanying proxy card in the enclosed postage-paid envelope or authorize the individuals named on the accompanying proxy card to vote your shares by calling the toll-free telephone number or by using the Internet as described in the instructions included with the accompanying proxy card. If your shares are held in the name of a bank, broker or other nominee, please follow the instructions on the voting instruction card furnished by such bank, broker or other nominee.

By Order of the Board of Directors

Dr. Vincent D. Mattera, Jr.

Director and Chief Executive Officer

May 6, 2021

Coherent, Inc.

5100 Patrick Henry Drive

Santa Clara, California 95054

Notice of Special Meeting of Stockholders

To Coherent Stockholders:

On March 25, 2021, Coherent, Inc. (which we refer to as “Coherent”), II-VI Incorporated (which we refer to as “II-VI”) and Watson Merger Sub Inc., a Delaware corporation and a wholly owned subsidiary of II-VI (which we refer to as “Merger Sub”), entered into an Agreement and Plan of Merger (which we refer to as the “merger agreement,” including as it may be amended from time to time). Pursuant to the merger agreement, Merger Sub will merge with and into Coherent (which we refer to as the “merger”) on the terms and subject to the conditions of the merger agreement, with Coherent continuing as the surviving entity in the merger and a wholly owned subsidiary of II-VI. A copy of the merger agreement is attached as Annex A to the accompanying joint proxy statement/prospectus.

NOTICE IS HEREBY GIVEN that a special meeting of Coherent stockholders (which we refer to as the “Coherent special meeting,” including any adjournments or postponements thereof) will be held virtually via live webcast on June 24, 2021, at 8:30 a.m., Pacific Time.

In light of ongoing developments related to the COVID-19 pandemic, the Coherent special meeting will be held solely in a virtual meeting format via live webcast. You will be able to virtually attend and vote at the Coherent special meeting by visiting www.virtualshareholdermeeting.com/COHR2021SM.

We will make available a list of stockholders of record entitled to vote at the Coherent special meeting available for viewing by Coherent stockholders for any purpose germane to the meeting beginning on June 14, 2021 at www.virtualshareholdermeeting.com/COHR2021SM. The list of our stockholders of record will remain available for viewing by Coherent stockholders during the Coherent special meeting.

We are pleased to notify you of and invite you to the Coherent special meeting. The purpose of the Coherent special meeting is to consider and vote upon the following matters:

The board of directors of Coherent has fixed the close of business on May 17, 2021 as the record date for the Coherent special meeting. Only holders of record of Coherent common stock as of the close of business on the record date for the Coherent special meeting are entitled to notice of, and to vote at, the Coherent special meeting or any adjournment or postponement thereof.

Your vote is very important regardless of the number of shares of Coherent common stock that you own. The merger cannot be completed without the approval of the Coherent merger proposal by Coherent stockholders.

Coherent’s board of directors recommends that holders of Coherent common stock vote “FOR” each of the proposals to be considered at the Coherent special meeting.

Whether or not you plan to attend the Coherent special meeting, we urge you to please promptly complete, sign, date and return the accompanying proxy card in the enclosed postage-paid envelope or authorize the individuals named on the accompanying proxy card to vote your shares by calling the toll-free telephone number or by using the Internet as described in the instructions included with the accompanying proxy card. If your shares are held in the name of a bank, broker or other nominee, please follow the instructions on the voting instruction card furnished by such bank, broker or other nominee.

By Order of the Board of Directors

Andy Mattes

Director, Chief Executive Officer and President

May 6, 2021

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS

The following are some questions that you may have about the merger, the II-VI special meeting or the Coherent special meeting, and brief answers to those questions. We urge you to read carefully the remainder of this joint proxy statement/prospectus because the information in this section does not provide all of the information that might be important to you with respect to the merger and the II-VI special meeting or the Coherent special meeting. Additional important information is also contained in the documents incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus.

In this joint proxy statement/prospectus, unless the context otherwise requires:

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In order to complete the merger, among other things:

II-VI is holding the II-VI special meeting to obtain approval of the II-VI share issuance proposal. II-VI shareholders will also be asked to approve the II-VI adjournment proposal. The approval of the II-VI adjournment proposal by II-VI shareholders is not required to complete the merger.

Coherent is holding the Coherent special meeting to obtain approval of the Coherent merger proposal. Coherent stockholders will also be asked to approve, on an advisory (non-binding) basis, the Coherent compensation proposal and to approve the Coherent adjournment proposal. Neither the approval of the Coherent compensation proposal nor the approval of the Coherent adjournment proposal by Coherent stockholders is required to complete the merger.

This document is also a prospectus that is being delivered to Coherent stockholders because, in connection with the merger, II-VI is offering shares of II-VI common stock to Coherent stockholders.

This joint proxy statement/prospectus contains important information about the merger agreement, the merger and the other proposals being voted on at the II-VI and Coherent special meetings. You should read it carefully and in its entirety. The enclosed materials allow you to have your shares of II-VI common stock voted by proxy without attending your meeting. Your vote is important and we encourage you to submit your proxy as soon as possible.

The Coherent special meeting will be held virtually at www.virtualshareholdermeeting.com/COHR2021SM, on June 24, 2021, at 8:30 a.m., Pacific Time. Online access will begin at 8:15 a.m., Pacific Time, and Coherent encourages its stockholders to access the meeting prior to the start time. You will be able to vote your shares electronically and submit questions online during the Coherent special meeting by logging in to the website listed above using the 16-digit control number included in your proxy card.

Even if you plan to attend your respective company’s special meeting, II-VI and Coherent recommend that you vote your shares in advance as described below so that your vote will be counted if you later decide not

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to or become unable to attend the applicable special meeting. Shares held in “street name” may be voted by you only if you obtain a signed legal proxy from your bank, broker or other nominee giving you the right to vote the shares at the applicable special meeting.

Under Pennsylvania law, II-VI shareholders are not required to consider and vote on the adoption of the merger agreement or the II-VI share issuance proposal, and II-VI shareholders are being asked to approve the II-VI share issuance proposal in order to satisfy Nasdaq requirements.

At the Coherent special meeting, Coherent stockholders will be asked to consider and vote on the following proposals:

In order to complete the merger, among other things, II-VI shareholders must approve the II-VI share issuance proposal and Coherent stockholders must approve the Coherent merger proposal. The approvals of the II-VI adjournment proposal, the Coherent compensation proposal or the Coherent adjournment proposal are not required to complete the merger, and the merger may be completed even if approval of one or more of those proposals is not obtained.

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At the effective time, each time- or performance-based Coherent RSU (other than any Coherent director RSU) that is outstanding immediately prior to the effective time will be converted into an award (which we refer to as a “converted RSU”) covering that number of shares of II-VI common stock, rounded down to the nearest whole share, equal to the product of (x) the number of shares of Coherent common stock subject to such award of Coherent RSUs (and, with respect to any Coherent RSUs that are subject to performance-vesting goals or metrics (which we refer to as “Coherent PSUs”)), the number of shares of Coherent common stock will be determined based on the greater of the target or actual level of achievement of such goals or metrics immediately prior to the effective time, as determined by the Coherent board (or a committee thereof) and (y) the sum of (A) the exchange ratio, and (B) the quotient obtained by dividing (i) the cash consideration by (ii) the volume weighted average price of a share of II-VI common stock for a ten trading day period, starting with the opening of trading on the 11th trading day prior to the closing date to the closing of trading on the second to last trading day prior to the closing date, as reported by Bloomberg.

For details on the treatment of Coherent equity awards, see “The Merger Agreement—Treatment of Coherent Equity Awards” beginning on page 157 of this joint proxy statement/prospectus.

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The investors have agreed to certain restrictions on transfer and standstill provisions, and will receive certain board governance and registration rights. The conversion price of the II-VI Series B convertible preferred stock will initially be $85.00 per share, subject to adjustments as set forth in the statement with respect to shares.

For more information on the terms of the investment agreement and the terms of the II-VI Series B convertible preferred stock, see “The Investment Agreement and the Statement with Respect to Shares” beginning on page 183 of this joint proxy statement/prospectus.

In considering the recommendations of the Coherent board, Coherent stockholders should be aware that Coherent directors and executive officers may have interests in the merger that are different from, or in addition to, the interests of Coherent stockholders generally. For a more complete description of these interests, see “The Merger—Interests of Coherent’s Directors and Executive Officers in the Merger” beginning on page 139 of this joint proxy statement/prospectus.

Each II-VI shareholder is entitled to cast one vote on each matter properly brought before the II-VI special meeting for each share of II-VI common stock that such holder owned of record as of the II-VI record date. As of the close of business on April 30, 2021, there were 105,007,546 outstanding shares of II-VI common stock. Virtual attendance at the II-VI special meeting is not required to vote. See below and “The II-VI Special Meeting—Proxies” beginning on page 59 of this joint proxy statement/prospectus for instructions on how to have your shares voted without attending the II-VI special meeting.

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Each Coherent stockholder is entitled to cast one vote on each matter properly brought before the Coherent special meeting for each share of Coherent common stock that such holder owned of record as of the Coherent record date. As of the close of business on April 30, 2021, there were 24,531,522 outstanding shares of Coherent common stock. Virtual attendance at the Coherent special meeting is not required to vote. See below and “The Coherent Special Meeting—Proxies” beginning on page 66 of this joint proxy statement/prospectus for instructions on how to have your shares voted without attending the Coherent special meeting.

There must be a quorum for the vote on the II-VI share issuance proposal to be taken at the II-VI special meeting. If there is no quorum, the II-VI special meeting may be adjourned or postponed to another date if the II-VI adjournment proposal is approved, which may subject II-VI to additional expense and delay or prevent the completion of the merger.

II-VI Proposal 2: II-VI adjournment proposal. Approval of the II-VI adjournment proposal requires the affirmative vote of at least a majority of the votes that all II-VI shareholders present at the II-VI special meeting, in person or by proxy, are entitled to cast. Shares of II-VI common stock not present or represented by proxy at the II-VI special meeting, whether due to a record holder’s failure to vote or a “street name” holder’s failure to instruct the stockholder’s bank, broker or other nominee how to vote, will have no effect on the outcome of the II-VI adjournment proposal. Abstentions will have the same effect as votes cast “AGAINST” the II-VI adjournment proposal.

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Coherent Proposal 2: Coherent compensation proposal. Approval of the Coherent compensation proposal requires the affirmative vote of the holders of a majority of the shares present or represented by proxy at the Coherent special meeting and entitled to vote on the Coherent compensation proposal. Shares of Coherent common stock not present or represented by proxy at the Coherent special meeting, whether due to a record holder’s failure to vote or a “street name” holder’s failure to instruct such holder’s bank, broker or other nominee how to vote, will have no effect on the outcome of the Coherent compensation proposal. Abstentions will have the same effect as votes cast “AGAINST” the Coherent compensation proposal.

Coherent Proposal 3: Coherent adjournment proposal. Approval of the Coherent adjournment proposal requires the affirmative vote of the holders of a majority of the shares present or represented by proxy at the Coherent special meeting and entitled to vote on the Coherent adjournment proposal. Shares of Coherent common stock not present or represented by proxy at the Coherent special meeting, whether due to a record holder’s failure to vote or a “street name” holder’s failure to instruct such holder’s bank, broker or other nominee how to vote, will have no effect on the outcome of the Coherent adjournment proposal. Abstentions will have the same effect as votes cast “AGAINST” the Coherent adjournment proposal.

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Record holders. Shares held directly in your name as the holder of record of II-VI common stock may be virtually voted at the II-VI special meeting via the II-VI special meeting website at www.virtualshareholdermeeting.com/IIVI2021SM. You will need the 16-digit control number included on your proxy card in order to access and vote at the II-VI special meeting.

Shares in “street name.” Shares of II-VI common stock held in “street name” may be voted at the II-VI special meeting by you only if you obtain a specific control number and follow the instructions from your bank, broker or other nominee.

Coherent

Record holders. Shares held directly in your name as the holder of record of Coherent common stock may be virtually voted at the Coherent special meeting via the Coherent special meeting website at www.virtualshareholdermeeting.com/COHR2021SM. You will need the 16-digit control number included on your proxy card in order to access and vote at the Coherent special meeting.

Shares in “street name.” Shares of Coherent common stock held in “street name” may be virtually voted at the Coherent special meeting via the Coherent special meeting website only if you obtain a specific control number and follow the instructions provided by your bank, broker or other nominee.

For more information on attending the special meetings, see “The II-VI Special Meeting” beginning on page 57 of this joint proxy statement/prospectus and “The Coherent Special Meeting” beginning on page 64 of this joint proxy statement/prospectus.

Additional information on voting procedures can be found under “The II-VI Special Meeting” on page 57 of this joint proxy statement/prospectus and under “The Coherent Special Meeting” on page 64 of this joint proxy statement/prospectus.

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If you are a II-VI shareholder and you properly sign your proxy card but do not mark the boxes showing how your shares of II-VI common stock should be voted on a matter, the shares represented by your properly signed proxy will be voted “FOR” the II-VI share issuance proposal and “FOR” the II-VI adjournment proposal, as applicable.

If you are a Coherent stockholder and you properly sign your proxy card but do not mark the boxes showing how your shares of Coherent common stock should be voted on a matter, the shares represented by your properly signed proxy will be voted “FOR” the Coherent merger proposal, “FOR” the compensation proposal and “FOR” the Coherent adjournment proposal, as applicable.

If you fail to submit a valid proxy and to virtually attend the applicable special meeting, or if your shares are held through a bank, brokerage firm or other nominee and you do not instruct your bank, brokerage firm or other nominee to vote your shares, your shares will not be voted on any of the matters being considered at the applicable special meeting and, if you are a Coherent stockholder, will have the effect of a vote “AGAINST” the Coherent merger proposal.

If your shares are held by a bank, brokerage firm or other nominee, you are considered the beneficial owner of shares held in “street name,” and your bank, brokerage firm or other nominee is considered the holder of

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record with respect to those shares. Your bank, brokerage firm or other nominee will send to you, as the beneficial owner, a package describing the procedure for voting your shares. You should follow the instructions provided by them to vote your shares.

All of the proposals to be voted on by II-VI shareholders at the II-VI special meeting and Coherent stockholders at the Coherent special meeting are non-routine matters. As a result, if your shares are held in “street name” through a brokerage firm and you do not provide voting instructions, your broker will not have discretionary authority to vote your shares at the II-VI special meeting or the Coherent special meeting, as applicable, and, accordingly, II-VI and Coherent do not expect any broker non-votes on any of the proposals at the special meetings. A broker non-vote occurs on an item when (i) a broker has discretionary authority to vote on at least one routine proposal at a meeting, but under stock exchange rules is not permitted to vote on other non-routine proposals without instructions from the beneficial owner of the shares and (ii) that broker exercises its discretionary authority on the routine proposal after the beneficial owner fails to provide such instructions, resulting in broker non-votes on each of the non-routine proposals.

If your shares are held by a broker, bank or other nominee, you should contact your broker, bank or other nominee to change your vote.

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Execution or revocation of a proxy will not in any way affect your right to virtually attend and vote at the applicable special meeting via the applicable special meeting website. Written notices of revocation and other communications relating to the revocation of proxies should be addressed to:

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In addition, if the merger agreement is terminated, the investment agreement will automatically terminate, the equity financing will not be completed in full, and II-VI will not issue the shares of II-VI Series B-2 convertible preferred stock pursuant to the investment agreement. The 75,000 shares of II-VI Series B-1 convertible preferred stock issued on March 31, 2021 pursuant to the investment agreement will remain issued and outstanding even if the merger agreement is terminated and the merger is not completed.

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Coherent will bear the entire cost of proxy solicitation, including preparation, assembly, printing and mailing of the notice of Coherent special meeting, proxy card, this joint proxy statement/prospectus and any additional materials furnished to Coherent stockholders. Copies of these materials will be furnished to brokerage houses, fiduciaries and custodians holding shares in their names that are beneficially owned by others to forward to those beneficial owners. In addition, Coherent may reimburse the costs of forwarding these materials to those beneficial owners. Coherent also may reimburse banks, brokerage firms, other nominees or their respective agents for their expenses in forwarding proxy materials to beneficial owners of Coherent common stock. Coherent’s directors, officers and employees also may solicit proxies by telephone, by facsimile, by mail, on the Internet or in person. They will not be paid any additional amounts for soliciting proxies. Coherent has engaged Georgeson LLC to aid in the solicitation of proxies from brokers, bank nominees and other institutional owners for approximately $25,000, plus reimbursement of related expenses.

Record holders. For shares held directly, please complete, sign, date and return each proxy card by mail (or submit your voting instructions by telephone or Internet as provided on each proxy card) or otherwise follow the voting instructions provided in this joint proxy statement/prospectus in order to ensure that all of your shares of II-VI common stock or Coherent common stock are voted.

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Shares in “street name.” For shares held in “street name” through a bank, broker or other nominee, you should follow the procedures provided by your bank, broker or other nominee to vote your shares.

Coherent stockholders: If you have any questions about the merger or how to submit your proxy or voting instruction card, or if you need additional copies of this joint proxy statement/prospectus or the enclosed proxy card or voting instruction card, you should contact:

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Some of the statements contained or incorporated by reference into this joint proxy statement/prospectus are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995.

Words such as “anticipate,” “estimate,” “continue,” “expect,” “project,” “intend,” “plan,” “believe,” “target,” “objective,” “goal,” “positions,” “prospects,” “potential,” “will,” “would,” “should,” “could,” “may” and words and terms of similar substance identify forward-looking statements, including any statements or discussions regarding timing of completion of the merger, expected benefits of the merger and the future operating or financial performance of II-VI, Coherent or the combined company identify forward-looking statements. All forward-looking statements are management’s present expectations or forecasts of future events and are subject to a number of factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. In addition to the factors relating to the merger discussed under the caption “Risk Factors” beginning on page 42 of this joint proxy statement/prospectus and the factors previously disclosed in II-VI’s and Coherent’s reports filed with the SEC, the following factors, among others, could cause actual results to differ materially from those described in the forward-looking statements:

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For any forward-looking statements made in this joint proxy statement/prospectus or in any documents incorporated by reference into this joint proxy statement/prospectus, II-VI and Coherent claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. You are cautioned not to place undue reliance on the forward-looking statements, which speak only as of the date of this joint proxy statement/prospectus or the dates of the documents incorporated by reference in this joint proxy statement/prospectus. Except as required by applicable law, neither II-VI nor Coherent undertakes to update these forward-looking statements to reflect facts, circumstances, assumptions or events that occur after the date the forward-looking statements are made.

For additional information about factors that could cause actual results to differ materially from those described in the forward-looking statements, see the reports that II-VI and Coherent have filed with the SEC as described under “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus.

We expressly qualify in their entirety all forward-looking statements attributable to either of us or any person acting on our behalf by the cautionary statements contained or referred to in this joint proxy statement/prospectus.

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RISK FACTORS

In addition to the other information contained in or incorporated by reference into this joint proxy statement/prospectus, including the matters addressed under the caption “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 40 of this joint proxy statement/prospectus, II-VI shareholders should carefully consider the following risk factors in deciding how to vote at the II-VI special meeting, and Coherent stockholders should carefully consider the following risk factors in deciding how to vote at the Coherent special meeting.

Risks Relating to the Merger

The merger is subject to approval by II-VI shareholders and Coherent stockholders.

In order for the merger to be completed, among other things, II-VI shareholders must approve the II-VI share issuance proposal and Coherent stockholders must approve the Coherent merger proposal. There can be no assurance that either approval will be obtained.

Because the market price of II-VI common stock fluctuates, Coherent stockholders cannot be certain of the market value of the merger consideration they will receive.

As a result of the merger, each share of Coherent common stock issued and outstanding immediately prior to the effective time (other than certain shares of Coherent common stock that are cancelled shares or dissenting shares) will be converted into the right to receive $220.00 in cash and 0.91 of a share of II-VI common stock. The exchange ratio will not be adjusted for changes in the market price of either II-VI common stock or Coherent common stock between the date of the merger agreement and the effective time. Changes in the price of II-VI common stock prior to the merger will affect the value that Coherent stockholders will receive as a result of the merger.

Stock price changes may result from a variety of factors, including general market and economic conditions, changes in Coherent’s and II-VI’s businesses, operations and prospects and regulatory considerations, many of which factors are beyond Coherent’s and II-VI’s control. Therefore, at the time of the Coherent special meeting, Coherent stockholders will not know the market value of the consideration to be received at the effective time. Coherent stockholders should obtain current market quotations for shares of II-VI common stock and for shares of Coherent common stock.

The market price of II-VI common stock after the merger may be affected by factors different from those affecting the shares of Coherent or II-VI currently.

As a result of the merger, Coherent stockholders will become II-VI shareholders. II-VI’s business differs from that of Coherent. Accordingly, the results of operations of the combined company and the market price of II-VI common stock after the completion of the merger may be affected by factors different from those currently affecting the independent results of operations of each of II-VI and Coherent. For a discussion of the businesses of II-VI and Coherent and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in this joint proxy statement/prospectus and referred to under “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus.

In addition, the issuance of shares of II-VI common stock in the merger could on its own have the effect of depressing the market price for II-VI common stock. In addition, many Coherent stockholders may decide not to hold the shares of II-VI common stock they receive as a result of the merger. Other Coherent stockholders, such as funds with limitations on their permitted holdings of stock in individual issuers, may be required to sell the shares of II-VI common stock they receive as a result of the merger. Any such sales of II-VI common stock could have the effect of depressing the market price for II-VI common stock.

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There can be no assurance that II-VI will be able to secure the funds necessary to pay the merger consideration, in a timely manner or at all.

II-VI intends to finance a portion of the merger consideration with the debt financing. To this end, II-VI has entered into the debt commitment letter containing commitments as of the date of this joint proxy statement/prospectus for a senior secured term loan “A” facility in an aggregate principal amount of $850 million, a senior secured term loan “B” facility in an aggregate principal amount of $2,800 million, a senior secured revolving credit facility in an aggregate principal amount of $350 million and a senior unsecured bridge loan facility in an aggregate principal amount of $1,125 million (which we refer to as the “bridge loan facility” and collectively with the other foregoing facilities, the “facilities”). However, as of the date of this joint proxy statement/prospectus, neither II-VI nor any of its subsidiaries has entered into definitive agreements for the debt financing (or other financing arrangements in lieu thereof), and the obligation of the lender to provide the debt financing under the debt commitment letter is subject to a number of customary conditions. There is a risk that these conditions will not be satisfied and the debt financing may not be available when required.

II-VI also intends to finance a portion of the merger consideration with the equity financing. To this end, on March 30, 2021, II-VI entered into the investment agreement. On March 31, 2021, II-VI and BCPE consummated the initial investment of $750.0 million pursuant to the investment agreement. Pursuant to the investment agreement and subject to the terms and conditions set forth therein, II-VI and the investors expect to consummate the subsequent investment of at least $1.05 billion, which may be increased by up to an additional $350.0 million, immediately prior to the closing of the merger. However, the purchase and issuance of the II-VI Series B-2 convertible preferred stock in the subsequent investment and the completion of the equity financing is subject to a number of customary conditions, and there can be no assurance that the equity financing will be completed.

In the event that the debt financing contemplated by the debt commitment letter or the subsequent investment contemplated by the investment agreement is not available, there is a risk that other financing may not be available on acceptable terms, in a timely manner or at all. Although II-VI’s obligation to consummate the merger is not conditioned upon the financings, if II-VI is unable to obtain the financings, the merger may be delayed or not completed, in which case II-VI would be in breach of its obligations under the merger agreement. See the section titled “The Merger—Financing” beginning on page 146 of this joint proxy statement/prospectus for more information.

The agreements that will govern the indebtedness to be incurred or assumed in connection with the merger are expected to contain various covenants that impose restrictions on II-VI and certain of its subsidiaries that may affect their ability to operate their businesses.

The agreements that will govern the indebtedness to be incurred or assumed in connection with the merger, including pursuant to the debt financing, are expected to contain various affirmative and negative covenants that will, subject to certain significant exceptions, restrict the ability of II-VI and certain of its subsidiaries to, among other things, have liens on their property, incur additional indebtedness, enter into sale and lease-back transactions, make loans, advances or other investments, make non-ordinary course asset sales, declare or pay dividends or make other distributions with respect to equity interests, and/or merge or consolidate with any other person or sell or convey certain of its assets to any one person, among other things. In addition, the definitive documentation governing certain of the facilities is expected to contain financial maintenance covenants that will require II-VI to maintain a certain leverage ratio and an interest coverage ratio at the end of each fiscal quarter. The ability of II-VI and its subsidiaries to comply with these provisions may be affected by events beyond their control. Failure to comply with these covenants could result in an event of default, which, if not cured or waived, could accelerate II-VI’s repayment obligations under the applicable definitive documentation so defaulted.

In connection with the merger, II-VI will incur significant additional indebtedness, which could adversely affect II-VI, including by decreasing II-VI’s business flexibility, and will increase its interest expense and the credit rating of the combined company could be downgraded.

The consolidated long-term debt of II-VI as of December 31, 2020 was approximately $1.4 billion. II-VI’s pro forma long-term debt as of December 31, 2020, after giving effect to the merger and the anticipated

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incurrence and extinguishment of indebtedness in connection therewith, will be approximately $4.9 billion. II-VI will have substantially increased indebtedness following completion of the merger in comparison to that of II-VI on a recent historical basis, which could have the effect, among other things, of reducing II-VI’s flexibility to respond to changing business and economic conditions and increasing II-VI’s interest expense. II-VI will also incur various costs and expenses associated with the financing. The amount of cash required to pay interest on II-VI’s increased indebtedness levels following completion of the merger and thus the demands on II-VI’s cash resources will be greater than the amount of cash flows required to service the indebtedness of II-VI prior to the transaction. The increased levels of indebtedness following completion of the merger could also reduce funds available for working capital, capital expenditures, acquisitions, share repurchases and other general corporate purposes and may create competitive disadvantages for II-VI relative to other companies with lower debt levels. If II-VI does not achieve the expected benefits and cost savings from the merger, or if the financial performance of the combined company does not meet current expectations, then II-VI’s ability to service its indebtedness may be adversely impacted.

In addition, II-VI’s credit ratings impact the cost and availability of future borrowings and, accordingly, II-VI’s cost of capital. II-VI’s ratings reflect each rating organization’s opinion of II-VI’s financial strength, operating performance and ability to meet II-VI’s debt obligations. In connection with the debt financing, it is anticipated that II-VI will seek ratings of its indebtedness from S&P and Moody’s. There can be no assurance that II-VI will achieve a particular rating or maintain a particular rating in the future. In addition, there can be no assurance that the credit ratings of existing II-VI debt will not be subject to a downgrade below investment grade. If a ratings downgrade were to occur or if the combined company fails to obtain an investment grade rating, the combined company could experience higher borrowing costs in the future and more restrictive debt covenants which would reduce profitability and diminish operational flexibility.

Moreover, II-VI may be required to raise substantial additional financing to fund working capital, capital expenditures, acquisitions or other general corporate requirements. II-VI’s ability to arrange additional financing will depend on, among other factors, II-VI’s financial position and performance, as well as prevailing market conditions and other factors beyond II-VI’s control. II-VI cannot assure you that it will be able to obtain additional financing on terms acceptable to II-VI or at all.

Integrating Coherent may be more difficult, costly or time-consuming than expected and II-VI may fail to realize the anticipated benefits of the merger, including expected financial and operating performance of II-VI after the merger.

The success of the merger will depend, in part, on the ability to realize the anticipated benefits and cost savings from II-VI acquiring Coherent. To realize the anticipated benefits and cost savings from the merger, II-VI must successfully integrate Coherent in a manner that permits those benefits and cost savings to be realized. The combined business’s ability to successfully manage this expanded business will depend, in part, upon management’s ability to implement an effective integration of the two companies and its ability to manage a combined business with significantly larger size and scope with the associated increased costs and complexity. If II-VI is not able to successfully achieve these objectives, or is not able to achieve these objectives on a timely basis, the anticipated benefits of the merger may not be realized fully or at all or may take longer to realize than expected. In addition, the actual cost savings of the merger could be less than anticipated.

II-VI and Coherent have operated and, until the completion of the merger, must continue to operate independently. It is possible that the integration process could result in the loss of key employees, the disruption of each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies that adversely affect the companies’ ability to maintain relationships with clients, customers, suppliers and employees or to achieve the anticipated benefits and cost savings of the merger. Integration efforts between the two companies may also divert management attention and resources. These integration matters could have an adverse effect on each of II-VI and Coherent during this transition period and for an undetermined period after completion of the merger on the combined company. All projections regarding the combined company’s business are, by their nature, estimates which are subject to risks and uncertainties. Business and financial measures of the

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combined company, including, but not limited to, revenue, free cash flow, synergies and dividend yield, are uncertain and subject to change based on changes in assumptions underlying such measures or other changes in circumstances, many of which may be outside of II-VI’s or Coherent’s control.

II-VI and Coherent may have difficulty attracting, motivating and retaining executives and other employees in light of the merger.

Uncertainty about the effect of the merger on II-VI and Coherent employees may have an adverse effect on II-VI and Coherent and consequently the combined company. This uncertainty may impair II-VI’s and Coherent’s ability to attract, retain and motivate personnel both before and after completion of the merger. II-VI and Coherent are dependent on the experience and industry knowledge of their officers and other key employees to execute their business plans. The success of the merger will depend in part on II-VI’s ability to retain the talents and dedication of key employees currently employed by Coherent. Employee retention may be particularly challenging during the pendency of the merger, as employees may feel uncertain about their future roles with the combined company. In addition, II-VI and Coherent may have to provide additional compensation in order to retain employees.

If key employees terminate their employment with II-VI or Coherent, or with the combined company after completion of the merger, the combined company’s business activities may be adversely affected and management’s attention may be diverted from successfully integrating II-VI and Coherent to hiring suitable replacements, all of which may cause the combined company’s business to suffer. In addition, II-VI and Coherent may not be able to locate or retain suitable replacements for any key employees who leave either company. Accordingly, no assurance can be given that II-VI will be able to attract or retain key employees following the completion of the merger to the same extent that II-VI or Coherent has been able to attract or retain employees in the past.

Regulatory approvals may not be received, may take longer than expected or may impose conditions that are not presently anticipated or that could have an adverse effect on the combined company following the merger.

Before the merger may be completed, certain waiting periods must expire or terminate and applicable approvals must be obtained under certain antitrust, competition and foreign investment laws and regulations. In deciding whether to grant regulatory clearances and approvals, the relevant governmental entities may consider, among other things, the effect of the merger on competition within their relevant jurisdiction. The terms and conditions of the approvals that are granted may impose requirements, limitations or costs or place restrictions on the conduct of II-VI’s business. There can be no assurance that regulators will not impose conditions, terms, obligations or restrictions and that such conditions, terms, obligations or restrictions will not have the effect of delaying completion of the merger or imposing additional material costs on or materially limiting the revenues of II-VI following the merger. In addition, neither II-VI nor Coherent can provide assurance that any such conditions, terms, obligations or restrictions will not result in the delay or abandonment of the merger. For a more detailed description of the regulatory review process, see “The Merger—Regulatory Approvals” beginning on page 145 of this joint proxy statement/prospectus.

The unaudited pro forma combined financial information included in this joint proxy statement/prospectus are preliminary and estimated, and the actual financial condition and results of operations of the combined company after the merger may differ materially.

The unaudited pro forma combined financial information in this joint proxy statement/prospectus are presented for illustrative purposes only and are not necessarily indicative of what the combined company’s actual financial condition or results of operations would have been had the merger been completed on the dates indicated. The unaudited pro forma combined financial information reflect adjustments, which are based upon preliminary estimates, to record the Coherent identifiable assets acquired and liabilities assumed at fair value and

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the resulting goodwill recognized. The purchase price allocation reflected in this joint proxy statement/prospectus is preliminary, and final allocation of the purchase price will be based upon the actual purchase price and the fair value of the assets and liabilities of Coherent as of the date of the completion of the merger. Accordingly, the final acquisition accounting adjustments may differ materially from the pro forma adjustments reflected in this joint proxy statement/prospectus. For more information, see “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 193 of this joint proxy statement/prospectus.

II-VI’s financial estimates are based on various assumptions that may not prove to be appropriate and such financial estimates may not be realized.

The financial estimates set forth in the forecast included under “The Merger—Certain Unaudited Prospective Financial Information” beginning on page 133 of this joint proxy statement/prospectus are based on assumptions of, and information available to, the management of II-VI at the time prepared. The assumptions underlying such financial estimates may not prove to be appropriate and any or all of such estimates may not be realized. The financial estimates can be adversely affected by known or unknown risks and uncertainties, many of which are beyond II-VI’s control. Many factors mentioned in this joint proxy statement/prospectus and II-VI’s other filings with the SEC incorporated by reference into this joint proxy statement/prospectus, including the risks outlined in this “Risk Factors” section and in II-VI’s public filings and the events and/or circumstances described under “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 40 of this joint proxy statement/prospectus will be important in determining II-VI’s future results. See “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus. As a result of these contingencies, actual future results may vary materially from II-VI’s estimates. In view of these uncertainties, the inclusion of II-VI’s financial estimates in this joint proxy statement/prospectus is not and should not be viewed as a representation that the forecasted results will be achieved. These financial estimates are based on II-VI’s internal financial forecasts and were not prepared with a view toward public disclosure or toward compliance with published guidelines of any regulatory or professional body. Further, any forward-looking statement speaks only as of the date on which it is made, and II-VI undertakes no obligation, other than as required by applicable law, to update its financial estimates herein to reflect events or circumstances after the date those financial estimates were prepared or to reflect the occurrence of anticipated or unanticipated events or circumstances. The II-VI financial estimates included in this joint proxy statement/prospectus have been prepared by, and are the responsibility of, II-VI. Moreover, II-VI’s independent auditors, Ernst & Young LLP, have not compiled, examined or performed any procedures with respect to II-VI’s prospective financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or its achievability, and, accordingly, Ernst & Young LLP assumes no responsibility for, and disclaims any association with, II-VI’s prospective financial information. The reports of Ernst & Young LLP incorporated by reference herein relate exclusively to the historical financial information of the entities named in those reports and do not cover any other information in this joint proxy statement/prospectus and should not be read to do so. See “The Merger—Certain Unaudited Prospective Financial Information” beginning on page 133 of this joint proxy statement/prospectus for more information.

Coherent’s financial estimates are based on various assumptions that may not prove to be appropriate and such financial estimates may not be realized.

The financial estimates set forth in the forecast included under “The Merger—Certain Unaudited Prospective Financial Information” beginning on page 133 of this joint proxy statement/prospectus are based on assumptions of, and information available to, the management of Coherent at the time prepared. The assumptions underlying such financial estimates may not prove to be appropriate and any or all of such estimates may not be realized. The financial estimates can be adversely affected by known or unknown risks and uncertainties, many of which are beyond Coherent’s control. Many factors mentioned in this joint proxy statement/prospectus and Coherent’s other filings with the SEC incorporated by reference into this joint proxy statement/prospectus, including the risks outlined in this “Risk Factors” section and in Coherent’s public filings and the events and/or circumstances described under “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 40 of this joint proxy statement/prospectus will be important in determining Coherent’s future results. See “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus. As a

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result of these contingencies, actual future results may vary materially from Coherent’s estimates. In view of these uncertainties, the inclusion of Coherent’s financial estimates in this joint proxy statement/prospectus is not and should not be viewed as a representation that the forecasted results will be achieved. These financial estimates are based on Coherent’s internal financial forecasts and were not prepared with a view toward public disclosure or toward compliance with published guidelines of any regulatory or professional body. Further, any forward-looking statement speaks only as of the date on which it is made, and Coherent undertakes no obligation, other than as required by applicable law, to update its financial estimates herein to reflect events or circumstances after the date those financial estimates were prepared or to reflect the occurrence of anticipated or unanticipated events or circumstances. The Coherent financial estimates included in this joint proxy statement/prospectus have been prepared by, and are the responsibility of, Coherent. Moreover, Coherent’s independent auditors, Deloitte & Touche LLP, have not compiled, examined or performed any procedures with respect to Coherent’s prospective financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or its achievability, and, accordingly, Deloitte & Touche LLP assumes no responsibility for, and disclaims any association with, Coherent’s prospective financial information. The reports of Deloitte & Touche LLP incorporated by reference herein relate exclusively to the historical financial information of the entities named in those reports and do not cover any other information in this joint proxy statement/prospectus and should not be read to do so. See “The Merger—Certain Unaudited Prospective Financial Information” beginning on page 133 of this joint proxy statement/prospectus for more information.

Certain of Coherent’s directors and executive officers may have interests in the merger that may differ from the interests of Coherent stockholders.

Coherent stockholders should be aware that some of Coherent’s directors and executive officers may have interests in the merger and have arrangements that are different from, or in addition to, those of Coherent stockholders generally. These interests and arrangements may create potential conflicts of interest. The Coherent board was aware of these respective interests and considered these interests, among other matters, when making its decision to adopt the merger agreement, and in recommending that holders of common stock vote to approve the Coherent merger proposal. For a more complete description of these interests, see “The Merger—Interests of Coherent’s Directors and Executive Officers in the Merger” beginning on page 139 of this joint proxy statement/prospectus.

The merger is subject to conditions, including certain conditions that may not be satisfied, and may not be completed on a timely basis, or at all. In addition, the merger agreement may be terminated in certain circumstances. Failure to complete the merger could have material and adverse effects on II-VI or Coherent.

The completion of the merger is subject to a number of conditions, which make the completion and timing of the completion of the merger uncertain. In addition, the merger agreement may be terminated in certain circumstances. If the merger is not completed on a timely basis, or at all, II-VI’s and Coherent’s respective ongoing businesses may be adversely affected and, without realizing any of the benefits of having completed the merger, II-VI and Coherent will be subject to a number of risks, including the following:

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In addition, if the merger is not completed, II-VI and Coherent may experience negative reactions from financial markets and from their respective customers and employees. II-VI and Coherent could also be subject to litigation related to any failure to complete the merger or to enforcement proceedings commenced against II-VI and Coherent to perform their respective obligations under the merger agreement. If the merger is not completed, neither II-VI nor Coherent can assure their shareholders or stockholders, respectively, that the risks described above will not materialize and will not adversely affect their respective businesses or financial results or the market price of their respective common stock.

Failure to consummate the merger will result in Coherent receiving little or no benefit from the termination fee Coherent paid in connection with terminating the March 9 Lumentum Merger Agreement.

If the merger agreement is terminated or if Coherent and II-VI do not consummate the transactions contemplated by the merger agreement, Coherent will receive little or no benefit from the termination fee it paid to Lumentum in the amount of $217.6 million in connection with the termination of the March 9 Lumentum Merger Agreement.

II-VI and Coherent have incurred, and will incur, significant transaction-related costs in connection with the merger.

Each of II-VI and Coherent has incurred and will incur substantial expenses in connection with the negotiation and completion of the transactions contemplated by the merger agreement, as well as the costs and expenses of filing, printing and mailing this joint proxy statement/prospectus, and filing and other fees paid or to be paid to the SEC and other regulatory agencies in connection with the merger. These fees and costs will be significant. In addition, II-VI will incur significant costs with respect to the financings for the cash consideration to be paid in connection with the merger. If the merger is not completed, II-VI and Coherent may have to recognize these expenses without realizing the expected benefits of the merger.

In addition, II-VI and Coherent also expect to incur a number of non-recurring transaction-related costs associated with combining the operations of the two companies and achieving desired synergies. Additional unanticipated costs may be incurred in the integration of the businesses of II-VI and Coherent. There can be no assurance that the elimination of certain duplicative costs, as well as the realization of other efficiencies related to the integration of the two businesses, will offset the incremental transaction-related costs over time. Thus, any net benefit may not be achieved in the near term, the long term or at all.

The closing of the merger may trigger change in control provisions in certain agreements to which Coherent is a party.

The closing of the merger may trigger change in control provisions in certain agreements to which Coherent is a party. If Coherent and II-VI are unable to negotiate waivers of those provisions, the counterparties may exercise their rights and remedies under the agreements, potentially terminating the agreements or seeking monetary damages. Even if Coherent and II-VI are able to negotiate waivers, the counterparties may require a fee for such waiver or seek to renegotiate the agreements on terms less favorable to Coherent or the combined company.

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II-VI and Coherent will be subject to business uncertainties while the merger is pending.

Uncertainty about the effect of the merger on employees, suppliers and customers may have an adverse effect on II-VI or Coherent. These uncertainties may impair II-VI’s or Coherent’s ability to attract, retain and motivate key personnel until the merger is completed, and could cause customers and others that deal with II-VI or Coherent to seek to change existing business relationships with II-VI or Coherent.

Each of II-VI and Coherent is subject to business uncertainties and contractual restrictions while the merger is pending, which could adversely affect each of Coherent’s and II-VI’s businesses and operations.

Under the terms of the merger agreement, Coherent and II-VI are subject to certain restrictions on the conduct of their respective business prior to completing the merger, which may adversely affect each party’s ability to execute certain of its business strategies. Such limitations could negatively affect each party’s businesses and operations prior to the completion of the merger. Furthermore, the process of planning to integrate two businesses and organizations for the post-merger period can divert management attention and resources and could ultimately have an adverse effect on each of Coherent and II-VI.

In connection with the merger, parties with which Coherent or II-VI does business may experience uncertainty associated with the merger, including with respect to current or future business relationships with Coherent, II-VI or the combined business. It is possible that some customers, suppliers and other persons with whom Coherent or II-VI has a business relationship may delay or defer certain business decisions or might decide to seek to terminate, change or renegotiate their relationships with Coherent or II-VI, as applicable, as a result of the merger, which could negatively affect Coherent’s or II-VI’s revenues, earnings and cash flows, as well as the market price of shares of II-VI common stock, regardless of whether the merger is completed. See “The Merger Agreement—Covenants and Agreements—Conduct of Businesses Prior to the Completion of the Merger” beginning on page 162 of this joint proxy statement/prospectus for a description of the restrictive covenants applicable to II-VI and Coherent.

Holders of II-VI and Coherent common stock will have a reduced ownership and voting interest in the combined company after the merger and the completion of the equity financing and will therefore have less voting influence over the combined company.

Holders of II-VI and Coherent common stock currently have the right to vote in the election of the board of directors and on other matters involving II-VI and Coherent, respectively. In the merger, each Coherent stockholder who receives shares of II-VI common stock will become a holder of common stock of the combined company, with a percentage ownership of the combined company that is smaller than such holder’s percentage ownership of Coherent. Upon completion of the merger, we estimate that Coherent stockholders as of immediately prior to the merger will collectively own approximately 15.0%, II-VI shareholders as of immediately prior to the merger (excluding as a result of the equity financing) will own approximately 70.7%, and the investors will own approximately 14.3% of the outstanding shares of common stock of the combined company (in each case, on an as-converted and fully diluted basis and without regard to the fact that immediately prior to the merger, certain holders may own both II-VI and Coherent stock). As a result, Coherent stockholders will have less voting influence on the combined company and may have less influence on its management and policies than they now have on Coherent, and II-VI shareholders will have less voting influence on the combined company and may have less influence on its management and policies than they now have on II-VI.

Coherent stockholders have appraisal rights subject to the requirements of the DGCL.

If the merger is completed and certain other statutory requirements described herein are met, Coherent stockholders who do not vote in favor of the Coherent merger proposal and otherwise properly perfect their appraisal rights may be entitled to a judicial determination of the “fair value” of their shares in connection with the merger under Section 262 of the DGCL, which generally entitles stockholders to receive in lieu of the merger

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consideration a cash payment of an amount determined by the Court of Chancery to be equal to the “fair value” of their Coherent common stock as of the effective time exclusive of any elements of value arising from the accomplishment or expectation of the merger, together with interest to be paid on the amount determined to be fair value, if any, as determined by the Court of Chancery. The appraised value would be determined by the Court of Chancery and could be less than, the same as or more than the value of the merger consideration. Coherent stockholders who have properly demanded appraisal rights must file a petition for appraisal with the Court of Chancery within 120 days after the effective date. Should a material number of Coherent’s stockholders exercise appraisal rights and should the Court of Chancery determine that the fair value of such shares of Coherent common stock is materially greater than the value of the merger consideration, it could have an adverse effect on the financial condition and results of operation of II-VI after the merger. For a more detailed description of the appraisal rights available to Coherent stockholders, see the section titled “The Merger—Appraisal Rights in the Merger” beginning on page 149 of this joint proxy statement/prospectus, which detailed description is qualified by reference to the full text of Section 262 of the DGCL as attached as Annex D to this joint proxy statement/prospectus.

Shareholder or stockholder litigation could prevent or delay the closing of the merger or otherwise negatively impact the business and operations of II-VI and Coherent.

II-VI and Coherent may incur costs in connection with the defense or settlement of any shareholder or stockholder lawsuits filed in connection with the merger. Such litigation could have an adverse effect on the financial condition and results of operations of II-VI and Coherent and could prevent or delay the consummation of the merger.

Holders of II-VI common stock have different rights from holders of Coherent common stock.

Upon completion of the merger, Coherent stockholders will no longer be stockholders of Coherent, a Delaware corporation, but will instead become shareholders of II-VI, a Pennsylvania corporation. As such, their rights as II-VI shareholders will be governed by Pennsylvania law and the terms of the II-VI charter and the II-VI bylaws, as they may be amended from time to time. Pennsylvania law and the terms of the II-VI charter and the II-VI bylaws are in some respects materially different than Delaware law and the terms of the Coherent charter and the Coherent bylaws, as they may be amended from time to time, which currently govern the rights of Coherent stockholders. See “Comparison of Stockholders’ Rights” beginning on page 218 of this joint proxy statement/prospectus for a discussion of the different rights associated with shares of II-VI common stock and shares of Coherent common stock.

The issuance of shares of II-VI Series B convertible preferred stock in connection with completing the equity financing will reduce the relative voting power of holders of II-VI common stock (including the voting power that current holders of Coherent common stock will have immediately after completion of the merger as holders of II-VI common stock), will dilute the ownership of such holders and may adversely affect the market price of II-VI common stock.

The shares of II-VI Series B-1 convertible preferred stock will initially be nonvoting. Following the expiration of the required waiting period under the HSR Act, the shares of II-VI Series B convertible preferred stock will have voting rights, voting as one class with II-VI common stock, on an as-converted basis, subject to limited exceptions. As a result, the issuance of II-VI Series B convertible preferred stock in connection with completing the equity financing will result in the immediate and substantial dilution to the interests of the holders of II-VI common stock (including the interests of current holders of Coherent common stock after the completion of the merger as holders of II-VI common stock).

Moreover, the conversion price of the II-VI Series B convertible preferred stock will initially be $85.00 per share, subject to adjustments as set forth in the statement with respect to shares. For more information on the terms of the investment agreement and of the II-VI Series B convertible preferred stock, see the section titled “The Investment Agreement and the Statement with Respect to Shares” beginning on page 183 of this joint proxy

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statement/prospectus. Any sales in the public market of the II-VI common stock issuable upon conversion of the II-VI Series B convertible preferred stock could adversely affect prevailing market prices of II-VI common stock. Sales by such holders of a substantial number of shares of II-VI common stock in the public market, or the perception that such sales might occur, could have a material adverse effect on the price of the II-VI common stock.

The holders of II-VI Series B convertible preferred shares have rights, preferences and privileges that are not held by, and are preferential to, the rights of holders of II-VI common stock.

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the affairs of II-VI, the holders of II-VI Series B convertible preferred stock are entitled to receive certain payments (i) prior to any amounts paid to holders of II-VI common stock and each other class or series of II-VI capital stock now existing or hereafter authorized, the terms of which do not expressly provide that such class or series ranks either (x) senior to the II-VI Series B convertible preferred stock as to dividend rights or distribution rights upon such a liquidation event or (y) on parity with the II-VI Series B convertible preferred stock as to dividend rights and distribution rights upon a such a liquidation event and (ii) on parity with II-VI’s 6% Series A Mandatory Convertible Preferred Stock, having no par value per share (which we refer to as the “II-VI Series A mandatory convertible preferred stock”), and each other class or series of II-VI capital stock established after the closing of the initial investment, the terms of which expressly provide that such class or series ranks on a parity basis with the II-VI Series B convertible preferred stock as to dividend rights and distribution rights upon such a liquidation event.

These provisions may make it more costly for a potential acquirer to engage in a business combination transaction with II-VI. Provisions that have the effect of potentially discouraging, delaying or preventing such a transaction could limit the opportunity for II-VI shareholders to receive a premium for their shares of II-VI common stock and could also affect the price that some investors are willing to pay for II-VI common stock. This could reduce the remaining amount of its assets, if any, available to distribute to holders of II-VI common stock.

In addition, the holders of II-VI Series B convertible preferred stock also have certain redemption, conversion and consent rights.

II-VI’s obligations to the holders of II-VI Series B convertible preferred stock could limit its ability to obtain additional financing or increase its borrowing costs, which could have an adverse effect on II-VI’s financial condition. These preferential rights could also result in divergent interests between the holders of shares of the II-VI Series B convertible preferred stock and holders of II-VI common stock.

The redemption right of the holders of II-VI Series B convertible preferred stock may result in the use of II-VI cash in such a way that could adversely affect II-VI’s business, financial condition or results of operations and, therefore, the interests of holders of II-VI common stock (including the interests of current holders of Coherent common stock after the completion of the merger as holders of II-VI common stock).

At any time on or after the ten year anniversary of the applicable issuance date of the shares of II-VI Series B convertible preferred stock and subject to the procedures set forth in the statement with respect to shares, each holder of such shares will have the right to require II-VI to redeem all of such holder’s shares of II-VI Series B convertible preferred stock for cash at a price per share equal to the sum of the applicable stated value for such shares plus accrued or declared and unpaid dividends on such shares that had not previously been added to such stated value. This may have the effect of reducing funds available for working capital, capital expenditures, acquisitions and other general corporate purposes, thereby negatively affecting the interests of holders of II-VI common stock (including the interests of current holders of Coherent common stock after the completion of the merger as holders of II-VI common stock).

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Holders of II-VI Series B convertible preferred stock can exercise significant control over II-VI, which could limit the ability of holders of II-VI common stock to influence the outcome of key transactions, including a change of control.

The shares of II-VI Series B-1 Convertible Preferred Stock will initially be nonvoting. Following the expiration of the required waiting period under the HSR Act, the shares of II-VI Series B convertible preferred stock will have voting rights, voting as one class with II-VI common stock, on an as-converted basis, subject to limited exceptions. As a result, the holders of shares of the II-VI Series B convertible preferred stock have the ability to significantly influence the outcome of any matter submitted for the vote of the holders of II-VI common stock. The investors are entitled to act separately in their own respective interests with respect to their ownership interests in II-VI and have the ability to substantially influence all matters that require approval by II-VI shareholders, including the approval of significant corporate transactions.

Additionally, II-VI may not undertake certain actions without the prior written approval of the holders of a majority of the issued and outstanding shares of II-VI Series B convertible preferred stock, voting separately from II-VI common stock. Subject to certain exceptions, II-VI must not: (1) alter or change the rights, preferences or privileges of II-VI Series B convertible preferred stock or amend, modify or supplement any provision of the organizational documents of II-VI in a manner that adversely affects the rights, powers, preferences or privileges of II-VI Series B convertible preferred stock; (2) authorize or issue any senior stock (as defined below) (or securities convertible into senior stock), or amend or alter II-VI’s articles of incorporation to increase the number of authorized or issued shares of II-VI Series B convertible preferred stock; (3) decrease the number of authorized shares of II-VI Series B convertible preferred stock (other than as permitted pursuant to a conversion, redemption or repurchase by II-VI thereof); (4) issue any shares of II-VI Series B convertible preferred stock (other than pursuant to the investment agreement); and (5) effect any voluntary deregistration or delisting with Nasdaq of the II-VI common stock.

Furthermore, II-VI may not, unless the investors otherwise consent in writing (or if such action is taken with respect to a Permitted Issuance (as defined in the investment agreement)), so long as the investors own at least 5% of the number of shares of II-VI Series B convertible preferred stock that they held immediately following the completion of either the initial investment (if the subsequent investment has not occurred) or the equity financing, (i) authorize or issue any parity stock (as defined below) and (ii) pay any cash dividend on II-VI common stock (other than ordinary dividends (as defined below)). II-VI also may not, unless the investors otherwise consent in writing (or if such action is taken with respect to a Permitted Issuance (as defined in the investment agreement)), so long as the investors own at least 25% of the number of shares of II-VI Series B convertible preferred stock that they held immediately following the completion of either the initial investment (if the subsequent investment has not occurred) or the equity financing, redeem, repurchase or otherwise acquire (or make or declare any dividend or distribution in respect of) any junior stock (as defined below) (subject to certain exceptions, including, among other things, ordinary dividends, non-cash dividends or other distributions paid pro rata to all holders of II-VI common stock and, if applicable, holders of II-VI Series B convertible preferred stock, repurchases of junior stock of up to $100 million on an aggregate annual basis and dividends on junior stock in kind or in the form of other junior securities or securities convertible into or exchange for such junior securities). Moreover, under the investment agreement, following the closing of the initial investment and for so long as the investors beneficially own shares of II-VI Series B convertible preferred stock (or shares of II-VI common stock issued upon the conversion thereof) that represent, in the aggregate and on an as-converted basis, at least 25% of the number of shares of II-VI common stock, on an as-converted basis, that they held immediately following the completion of either the initial investment (if the subsequent investment has not occurred) or the equity financing, the investors will have the right to nominate one designee and to designate one observer to the II-VI board. Circumstances may occur in which the interests of the investors could conflict with the interests of II-VI’s other shareholders.

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Risks Relating to the Combined Company Following the Merger

Although II-VI expects that its acquisition of Coherent will result in cost savings, synergies and other benefits, the combined company may not realize those benefits because of integration difficulties and other challenges.

The success of II-VI’s acquisition of Coherent will depend in large part on the success of the management of the combined company in integrating the customers, suppliers, manufacturing operations, quality systems, information systems, strategies, technologies and personnel of the two companies following the completion of the merger. The combined company may fail to realize some or all of the anticipated benefits of the merger if the integration process takes longer than expected or is more costly than expected. The failure of the combined company to meet the challenges involved in successfully integrating the operations of the two companies or to otherwise realize any of the anticipated benefits of the merger, including additional cost savings and synergies, could impair the operations of the combined company. In addition, II-VI anticipates that the overall integration of Coherent will be a time-consuming and expensive process that, without favorable market conditions proper planning and effective and timely implementation and leadership, could significantly disrupt the combined company’s business.

Potential difficulties the combined company may encounter in the integration process include the following:

The anticipated cost savings, synergies and other benefits of the merger assume a successful integration of the companies and are based on projections and other assumptions, which are inherently uncertain. Even if integration is successful, anticipated cost savings, synergies and other benefits may not be achieved.

The market price of II-VI common stock may decline in the future as a result of the merger.

The market price of II-VI common stock may decline in the future as a result of the merger for a number of reasons, including:

Many of these factors are beyond the control of II-VI. As a consequence, current II-VI shareholders and Coherent stockholders, who will become holders of II-VI common stock after completion of the merger, could lose the value of their investment in II-VI common stock.

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The merger may not be accretive on the projected timeline and may cause dilution to the combined company’s earnings per share, which may negatively affect the market price of the II-VI common stock.

II-VI currently anticipates that the merger will be accretive to earnings per share (on an adjusted earnings basis) in the second year after the merger. This expectation is based on preliminary estimates which may materially change. The combined company could also encounter additional transaction-related costs or other factors such as the failure to realize all of the benefits anticipated in the merger. All of these factors could cause dilution to the combined company’s earnings per share or decrease or delay the expected accretive effect of the merger and cause a decrease in the market price of II-VI common stock.

The combined company’s future results will suffer if it does not effectively manage its expanded operations following the merger.

Following the merger, the size of the business of the combined company will increase significantly beyond the current size of either II-VI’s or Coherent’s current businesses. The combined company’s future success depends, in part, upon its ability to manage this expanded business, which may pose substantial challenges for management, including challenges related to the management and monitoring of new operations and associated increased costs and complexity. There can be no assurance that the combined company will be successful or that it will realize the expected operating efficiencies, cost savings, revenue enhancements and other benefits currently anticipated from the merger.

II-VI and Coherent face competition, which is expected to intensify after the closing of the merger and which may reduce the market share and profits of II-VI after consummation of the merger.

Competition in the industries in which II-VI and Coherent operate is intense. Increased competition could hurt II-VI’s and Coherent’s businesses, hinder their market share expansion and lead to pricing pressures that may adversely impact their margins and revenues. If the combined company is unable to successfully compete following the merger, its business, prospects, liquidity, financial condition and results of operations could be materially and adversely affected.

Following the consummation of the merger, the combined company’s competitive position could be weakened by strategic alliances or consolidation within the combined company’s industries or the development of new technologies by competitors. The combined company’s ability to compete successfully will depend on how well it markets its products and services and on its ability to anticipate and respond to various competitive factors affecting its industries, including changes in customer preferences, and changes in the product offerings or pricing strategies of the combined company’s competitors.

After the consummation of the merger, competition could materially adversely affect the combined company in several ways, including (i) the loss of customers and market share, (ii) the combined company’s need to lower prices or increase expenses to remain competitive and (iii) the loss of business relationships within II-VI’s existing markets.

II-VI is expected to incur substantial expenses related to the merger and integration.

II-VI is expected to incur substantial expenses in connection with the merger and the related integration. There are a large number of processes, policies, procedures, operations, technologies and systems that may need to be integrated, including purchasing, accounting and finance, sales, payroll, pricing and benefits.

While II-VI has assumed that a certain level of expenses will be incurred, there are many factors beyond its control that could affect the total amount or the timing of the integration expenses. Moreover, many of the expenses that will be incurred are, by their nature, difficult to estimate accurately. These expenses could, particularly in the near term, exceed the savings that II-VI expects to achieve from the elimination of duplicative expenses and the realization of economies of scale and cost savings. These integration expenses likely will result in the combined company taking significant charges against earnings following the completion of the merger, and the amount and timing of such charges are uncertain at present.

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Following the consummation of the merger, II-VI will be bound by all of the obligations and liabilities of both companies.

Following the consummation of the merger, the combined company will become bound by all of the obligations and liabilities of Coherent in addition to II-VI’s obligations and liabilities existing prior to the consummation of the merger. Neither II-VI nor Coherent can predict the financial condition of the combined company at the time of the combination or the ability of the combined company to satisfy its obligations and liabilities.

The merger may result in a loss of suppliers and strategic alliances and may result in the termination of existing contracts.

Following the merger, some of the suppliers of II-VI or Coherent may increase prices or may terminate or scale back their business relationship with, or even become competitors of, the combined company. II-VI and Coherent have contracts with suppliers, vendors, and other business partners which may require II-VI or Coherent to obtain consents from these other parties in connection with the merger, which may not be obtained at all or on favorable terms. If supplier relationships or strategic alliances are adversely affected by the merger, or if the combined company, following the merger, loses the benefits of the contracts of II-VI or Coherent, the combined company’s business and financial performance could suffer.

Following the merger, the combined company will have a substantial amount of debt, which could adversely affect its business, financial condition or results of operations and prevent it from fulfilling its debt-related obligations.

Following the merger, the combined company will have a substantial amount of debt. As of December 31, 2020, on a pro forma basis, the combined company would have had approximately $4.9 billion of outstanding long-term debt (including under its outstanding debt securities and borrowings under II-VI’s credit facilities). The combined company’s substantial debt could have important consequences for the holders of II-VI common stock, including:

The combined company may not generate sufficient cash flow from operations, together with any future borrowings, to enable the combined company to pay its indebtedness, or to fund the combined company’s other liquidity needs. The combined company may need to refinance all or a portion of its indebtedness, on or before its maturity. The combined company may not be able to refinance any of its indebtedness on commercially reasonable terms or at all. In addition, the combined company may incur additional indebtedness in order to

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finance its operations, to fund acquisitions, or to repay existing indebtedness. If the combined company cannot service its indebtedness, it may have to take actions such as selling assets, seeking additional debt or equity or reducing or delaying capital expenditures, strategic acquisitions, investments and alliances. Any such actions, if necessary, may not be able to be effected on commercially reasonable terms or at all, or on terms that would be advantageous to the combined company’s stockholders or on terms that would not require II-VI to breach the terms and conditions of its existing or future debt agreements.

Risks Relating to II-VI’s Business

You should read and consider risk factors specific to II-VI’s business that will also affect the combined company after the merger. These risks are described in the sections entitled “Risk Factors” in II-VI’s Annual Report on Form 10-K for the fiscal year ended June 30, 2020 and in other documents incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus for the location of information incorporated by reference into this joint proxy statement/prospectus.

Risks Relating to Coherent’s Business

You should read and consider risk factors specific to Coherent’s business that will also affect the combined company after the merger. These risks are described in the sections entitled “Risk Factors” in Coherent’s Annual Report on Form 10-K for the fiscal year ended October 3, 2020, in Coherent’s Quarterly Report on Form 10-Q for the fiscal quarter ended January 2, 2021 and in other documents incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 245 of this joint proxy statement/prospectus for the location of information incorporated by reference into this joint proxy statement/prospectus.

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THE II-VI SPECIAL MEETING

This section contains information for II-VI shareholders about the special meeting that II-VI has called to allow II-VI shareholders to consider and vote on the II-VI share issuance proposal and other related matters. This joint proxy statement/prospectus is accompanied by a notice of the special meeting of II-VI shareholders and a form of proxy card that the II-VI board is soliciting for use at the II-VI special meeting and at any adjournments or postponements of the II-VI special meeting.

Date, Time and Place of the Meeting

The II-VI special meeting will be held virtually on June 24, 2021, at 11:30 a.m., Eastern Time.

In light of ongoing developments related to the COVID-19 pandemic, II-VI has elected to hold the II-VI special meeting solely by means of remote communication via live webcast. II-VI shareholders will be able to virtually attend and vote at the II-VI special meeting by visiting www.virtualshareholdermeeting.com/IIVI2021SM. II-VI shareholders must first register at the special meeting website in order to obtain a unique meeting invitation by electronic mail.

II-VI has retained Broadridge Financial Solutions, Inc. to host the live webcast of the II-VI special meeting. You may call the technical support number that will be available 30 minutes before the II-VI special meeting begins at www.virtualshareholdermeeting.com/IIVI2021SM if you encounter any technical difficulty logging-in or otherwise accessing the II-VI special meeting.

Matters to Be Considered

At the II-VI special meeting, II-VI shareholders will be asked to consider and vote upon the following proposals:

II-VI will not transact on other business at the II-VI special meeting, except for business properly brought before the II-VI special meeting or any adjournment or postponement thereof.

Recommendation of the II-VI Board

The II-VI board recommends that you vote “FOR” the II-VI share issuance proposal and “FOR” the II-VI adjournment proposal. See “The Merger—II-VI’s Reasons for the Merger; Recommendation of the II-VI Board” beginning on page 123 of this joint proxy statement/prospectus for a more detailed discussion of the II-VI board’s recommendation.

Record Date and Quorum

The II-VI board has fixed the close of business on May 17, 2021 as the II-VI record date for determination of II-VI shareholders entitled to notice of and to vote at the II-VI special meeting. As of April 30, 2021, there were 105,007,546 shares of II-VI common stock outstanding.

The presence, in person (virtually) or represented by proxy, of shareholders entitled to cast at least a majority of the votes that all shareholders are entitled to cast on the II-VI record date will constitute a quorum at the II-VI special meeting. If you are a II-VI shareholder and you fail to submit a proxy or to vote at the II-VI special meeting, your shares of II-VI common stock will not be counted towards a quorum. Abstentions are considered present for purposes of establishing a quorum. There must be a quorum for votes on the II-VI share

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issuance proposal to be taken at the II-VI special meeting. If there is no quorum, the II-VI special meeting may be adjourned or postponed to another date if the II-VI adjournment proposal is approved at the II-VI special meeting.

At the II-VI special meeting, each share of II-VI common stock is entitled to one (1) vote on all matters properly submitted to II-VI shareholders.

As of April 30, 2021, II-VI directors and executive officers and their affiliates owned and were entitled to vote approximately 2.3 million shares of II-VI common stock (which aggregate number is inclusive of restricted shares of II-VI common stock, II-VI common stock underlying granted but unvested II-VI restricted stock units, II-VI stock options exercisable within 60 days of the II-VI record date, II-VI restricted stock units vesting within 60 days of the record date, and II-VI common stock indirectly owned), representing approximately 2.2% of the outstanding shares of II-VI common stock. We currently expect that II-VI’s directors and executive officers will vote their shares in favor of the II-VI share issuance proposal, although none of them has entered into any agreements obligating them to do so.

Vote Required; Treatment of Abstentions and Failure to Vote

II-VI share issuance proposal:

II-VI adjournment proposal:

For more information on attending and voting at the II-VI special meeting, see “—Virtually Attending the II-VI Special Meeting” below in this joint proxy statement/prospectus.

Virtually Attending the II-VI Special Meeting

If you wish to virtually attend the II-VI special meeting via the II-VI special meeting website, you must (i) be a II-VI shareholder of record at the close of business on May 17, 2021, (ii) hold your shares of II-VI common stock beneficially in the name of a broker, bank or other nominee as of the II-VI record date or (iii) hold a valid proxy for the II-VI special meeting.

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To enter the II-VI special meeting website and virtually attend the II-VI special meeting, you must first register at the II-VI special meeting website by visiting www.virtualshareholdermeeting.com/IIVI2021SM in order to obtain a unique meeting invitation by email. If you hold your shares of II-VI common stock in street name beneficially through a broker, bank or other nominee and you wish to virtually attend and vote at the II-VI special meeting via the II-VI special meeting website, you must provide a legal proxy from your bank, broker or other nominee during registration to obtain a virtual control number. If you are unable to obtain a legal proxy from your bank, broker or other nominee, you will be able to register to attend the II-VI special meeting, but may not vote your shares at the II-VI special meeting.

If you plan to virtually attend and vote at the II-VI special meeting via the II-VI special meeting website, II-VI still encourages you to submit your voting instructions in advance by the Internet, telephone or (if you received a paper copy of the proxy materials) by mail so that your vote will be counted even if you later decide not to virtually attend the II-VI special meeting via the II-VI special meeting website. Submitting your proxy by the Internet, telephone or mail will not limit your right to virtually attend and vote at the II-VI special meeting via the II-VI special meeting website if you later decide to do so.

Proxies

A II-VI shareholder may vote by in person (virtually) or by proxy at the II-VI special meeting. If you hold your shares of II-VI common stock in your name as a holder of record, to submit a proxy, you, as a II-VI shareholder, may use one of the following methods:

II-VI requests that II-VI shareholders submit a proxy by telephone, over the Internet or by completing and signing the accompanying proxy card and returning it to II-VI as soon as possible in the enclosed postage-paid envelope. When the accompanying proxy card is returned properly executed, the shares of II-VI common stock represented by it will be voted at the II-VI special meeting in accordance with the instructions contained on the proxy card.

If your shares are held in “street name” by a broker, bank or other nominee, you will receive instructions from your broker, bank or other nominee that you must follow in order to vote your shares of II-VI common stock, which will identify which of the above choices are available to you in order to submit a proxy.

If you submit your voting instructions by proxy, regardless of the method you choose to submit your proxy, the individuals named on the enclosed proxy card, and each of them, with full power of substitution and resubstitution, will vote your shares of II-VI common stock in the way that you indicate. When completing the telephone or Internet processes or the proxy card, you may specify whether your shares of II-VI common stock should be voted “FOR” or “AGAINST” or to “ABSTAIN” from voting on all, some or none of the specific items of business to come before the II-VI special meeting.

If you properly sign your proxy card but do not mark the boxes showing how your shares of II-VI common stock should be voted on a matter, the shares of II-VI common stock represented by your properly signed proxy will be voted “FOR” the II-VI share issuance proposal and “FOR” the II-VI adjournment proposal.

Every vote is important. Accordingly, you should sign, date and return the enclosed proxy card, or submit a proxy via the Internet or by telephone, whether or not you plan to attend the II-VI special meeting. Sending in

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your proxy card by mail, by telephone or on the Internet will not prevent you from voting your shares personally at the meeting because you may revoke your proxy at any time before it is voted at the meeting.

Shares Held in Street Name

If your shares are held in “street name” through a broker, bank or other nominee, you must instruct the broker, bank or other nominee on how to vote your shares. Your broker, bank or other nominee will vote your shares only if you provide specific instructions on how to vote by following the instructions provided to you by your broker, bank or other nominee.

You may not vote shares held in “street name” by returning a proxy card directly to II-VI or by voting at the II-VI special meeting unless you provide a “legal proxy” giving you the right to vote the shares, which you must obtain from your broker, bank or other nominee. If you choose to vote your shares at the II-VI special meeting, please bring proof of identification and the proxy from your bank, broker or other nominee.

Further, brokers, banks or other nominees who hold shares of II-VI common stock on behalf of their customers may not give a proxy to II-VI to vote those shares with respect to any of the proposals without specific instructions from their customers, as brokers, banks, and other nominees do not have discretionary voting power on the proposals that will be voted upon at the II-VI special meeting.

Revocability of Proxies

If you are a II-VI shareholder of record, you may revoke your proxy at any time before it is voted by:

If you hold your shares of II-VI common stock through a broker, bank or other nominee, you should contact your broker, bank or other nominee to change your vote.

Attendance at the II-VI special meeting will not in and of itself constitute revocation of a proxy. A revocation or later-dated proxy received by II-VI after the vote will not affect the vote. II-VI’s Secretary’s mailing address is: II-VI Incorporated, 375 Saxonburg Boulevard, Saxonburg, Pennsylvania 16056, Attn: Secretary. If the II-VI special meeting is postponed or adjourned, it will not affect the ability of II-VI shareholders as of the II-VI record date to exercise their voting rights or to revoke any previously-granted proxy using the methods described above.

Adjournments and Postponements

Although it is not currently expected, the II-VI special meeting may be adjourned or postponed on one or more occasions for the purpose of soliciting additional proxies if there are insufficient votes at the time of the II-VI special meeting to approve the II-VI share issuance proposal or if a quorum is not present at the II-VI special meeting.

II-VI may also postpone or adjourn the II-VI special meeting to allow reasonable additional time for the filing or mailing of any supplemental or amended disclosure required under applicable law and for such supplemental or amended disclosure to be disseminated and reviewed by II-VI shareholders prior to the II-VI special meeting.

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An adjournment generally may be made with the affirmative vote of the holders of a majority of the shares of II-VI common stock present in person or represented by proxy and entitled to vote thereon.

Delivery of Proxy Materials

As permitted by applicable law, only one copy of this joint proxy statement/prospectus is being delivered to II-VI shareholders residing at the same address, unless such II-VI shareholders have notified II-VI of their desire to receive multiple copies of the joint proxy statement/prospectus.

II-VI will promptly deliver, upon oral or written request, a separate copy of the joint proxy statement/prospectus to any II-VI shareholders residing at an address to which only one copy of such document was mailed. A II-VI shareholder who wishes to receive a separate copy of this joint proxy statement/prospectus may obtain one, without charge, by sending a request to II-VI Incorporated, 375 Saxonburg Boulevard, Saxonburg, Pennsylvania 16056, Attention: Mark Lourie or by calling (724) 352-4455.

Solicitation of Proxies; Payment of Solicitation Expenses

This joint proxy statement/prospectus is being provided to holders of shares of II-VI common stock in connection with the solicitation of proxies by the II-VI board to be voted at the II-VI special meeting and at any adjournments or postponements of the II-VI special meeting. II-VI will bear all costs and expenses in connection with the solicitation of proxies, including the costs of filing, printing and mailing this joint proxy statement/prospectus for the II-VI special meeting.

To assist in the solicitation of proxies, II-VI has retained MacKenzie Partners, Inc., for a fee of $25,000 plus reimbursement of out-of-pocket expenses for its services. II-VI and its proxy solicitor may also request banks, brokers and other intermediaries holding shares of II-VI common stock beneficially owned by others to send this joint proxy statement/prospectus to, and obtain proxies from, the beneficial owners and may reimburse such record holders for their reasonable out-of-pocket expenses in so doing. Solicitation of proxies by mail may be supplemented by telephone and other electronic means, advertisements and personal solicitation by the directors, officers or employees of II-VI. No additional compensation will be paid to our directors, officers or employees for solicitation.

Other Matters to Come Before the II-VI Special Meeting

II-VI management knows of no other business to be presented at the II-VI special meeting, but if any other matters are properly presented to the meeting or any adjournments thereof, the persons named in the proxies will vote upon them in accordance with the II-VI board’s recommendations.

Assistance

If you need assistance in completing your proxy card, have questions regarding II-VI’s special meeting or would like additional copies of this joint proxy statement/prospectus, please contact II-VI at II-VI Incorporated, 375 Saxonburg, PA 16056, Attention: Mark Lourie, Telephone (724) 352-4455.

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II-VI PROPOSALS

Proposal 1: II-VI Share Issuance Proposal

II-VI is asking II-VI shareholders to approve the issuance of (i) shares of II-VI common stock pursuant to the terms of the merger agreement in the amounts necessary to complete the merger, (ii) shares of II-VI Series B-2 convertible preferred stock in the subsequent investment pursuant to the terms of the investment agreement and (iii) shares of II-VI common stock upon any conversion of the II-VI Series B convertible preferred stock issued in the equity financing. II-VI shareholders should read this joint proxy statement/prospectus carefully and in its entirety, including the annexes, for more detailed information concerning the merger agreement, the investment agreement, the statement with respect to shares, the merger, the equity financing, the issuance of shares of II-VI common stock in connection with the merger, the issuance of shares of II-VI Series B convertible preferred stock in connection with the equity financing and the other transactions contemplated by the merger agreement and the investment agreement.

A copy of the merger agreement is attached to this joint proxy statement/prospectus as Annex A and a summary of the terms is included under “The Merger Agreement” beginning on page 156 of this joint proxy statement/prospectus. A copy of each of the investment agreement and statement with respect to shares is attached to this joint proxy statement/prospectus as Annex B and Annex C, respectively, and a summary of each of the investment agreement and statement with respect to shares is included under “The Investment Agreement and the Statement with Respect to Shares” beginning on page 183 of this joint proxy statement/prospectus.

After careful consideration, the II-VI board determined that the merger, the merger agreement, the investment agreement and the transactions contemplated by the merger agreement and the investment agreement are advisable and in the best interests of II-VI and II-VI shareholders and adopted and approved the merger agreement, the investment agreement, the merger and the other transactions contemplated by the merger agreement and the investment agreement. Accordingly, the II-VI board directed that the II-VI share issuance proposal be submitted to II-VI shareholders and recommended that II-VI shareholders approve the II-VI share issuance proposal. See “The Merger—II-VI’s Reasons for the Merger; Recommendation of the II-VI Board” beginning on page 123 of this joint proxy statement/prospectus for a more detailed discussion of the II-VI board’s recommendation.

The II-VI board recommends a vote “FOR” the II-VI share issuance proposal.

Proposal 2: II-VI Adjournment Proposal

The II-VI special meeting may be adjourned to a later date or dates, if necessary or appropriate, including to solicit additional proxies if there are insufficient votes at the time of the II-VI special meeting to approve the II-VI share issuance proposal.

If, at the II-VI special meeting, the number of shares of II-VI common stock present or represented and voting in favor of the II-VI share issuance proposal is insufficient to approve the II-VI share issuance proposal, II-VI intends to move to adjourn the II-VI special meeting in order to enable the II-VI board to solicit additional proxies for approval of the share issuance. In that event, II-VI will ask II-VI shareholders to vote upon the II-VI adjournment proposal, but not the II-VI share issuance proposal. II-VI does not intend to call a vote on the II-VI adjournment proposal to solicit additional proxies if the II-VI share issuance proposal is approved at the II-VI special meeting. Any determination of whether it is necessary or appropriate to adjourn the II-VI special meeting to solicit additional proxies will be made on or behalf of II-VI by the presiding officer of the II-VI special meeting (as determined in accordance with the II-VI bylaws) and will be consistent with the terms of the merger agreement.

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In this proposal, II-VI is asking II-VI shareholders to authorize the holder of any proxy solicited by the II-VI board on a discretionary basis to vote in favor of adjourning the II-VI special meeting to another time and place (if any) for the purpose of soliciting additional proxies, including the solicitation of proxies from II-VI shareholders who have previously voted.

The II-VI board recommends a vote “FOR” the II-VI adjournment proposal.

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THE COHERENT SPECIAL MEETING

This section contains information for Coherent stockholders about the special meeting that Coherent has called to allow Coherent stockholders to consider and vote on the merger agreement and other related matters. This joint proxy statement/prospectus is accompanied by a notice of the special meeting of Coherent stockholders and a form of proxy card that the Coherent board is soliciting for use at the Coherent special meeting and at any adjournments or postponements of the Coherent special meeting.

Date, Time and Place of the Meeting

The Coherent special meeting is scheduled to be held virtually via live webcast on June 24, 2021, beginning at 8:30 a.m., Pacific Time, unless postponed to a later date.

In light of ongoing developments related to the COVID-19 pandemic, Coherent has elected to hold the Coherent special meeting solely by means of remote communication via live webcast. Coherent stockholders will be able to virtually attend and vote at the Coherent special meeting by visiting www.virtualshareholdermeeting.com/COHR2021SM. Coherent stockholders must first register at the special meeting website in order to obtain a unique meeting invitation by electronic mail. Coherent stockholders may request access to the list of Coherent stockholders entitled to vote at the Coherent special meeting during the live webcast.

Coherent has retained Broadridge LLC to host the live webcast of the Coherent special meeting. On the day of the Coherent special meeting, Broadridge LLC may be contacted toll-free at (800) 542-1061 to answer any questions regarding how to virtually attend the Coherent special meeting or if you encounter any technical difficulty accessing or during the Coherent special meeting.

Matters to Be Considered

At the Coherent special meeting, holders of Coherent common stock will be asked to consider and vote upon the following proposals:

Recommendation of the Coherent Board

The Coherent board recommends that you vote “FOR” the Coherent merger proposal, “FOR” the Coherent compensation proposal and “FOR” the Coherent adjournment proposal. See “The Merger—Coherent’s Reasons for the Merger; Recommendation of the Coherent Board” beginning on page 98 of this joint proxy statement/prospectus for a more detailed discussion of the Coherent board’s recommendation.

Record Date and Quorum

The Coherent board has fixed the close of business on May 17, 2021 as the Coherent record date for determination of Coherent stockholders entitled to notice of and to vote at the Coherent special meeting. As of April 30, 2021, there were 24,531,522 shares of Coherent common stock outstanding.

Holders of a majority of the shares of Coherent common stock outstanding on the record date must be present, either virtually at the Coherent special meeting or by proxy, to constitute a quorum at the Coherent special meeting. If you are a Coherent stockholder and you fail to submit a proxy or to attend the Coherent special meeting, your shares of Coherent common stock will not be counted towards a quorum. Abstentions are considered present for purposes of establishing a quorum.

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At the Coherent special meeting, each share of Coherent common stock is entitled to one vote on all matters properly submitted to holders of Coherent common stock.

As of April 30, 2021, Coherent directors and executive officers and their affiliates owned and were entitled to vote approximately 168,075 shares of Coherent common stock (which aggregate number is inclusive of Coherent RSUs vesting within 60 days of the Coherent record date and Coherent common stock indirectly owned), representing less than 1% of the outstanding shares of Coherent common stock. We currently expect that Coherent’s directors and executive officers will vote their shares in favor of the Coherent merger proposal, although none of them has entered into any agreements obligating them to do so.

Vote Required; Treatment of Abstentions and Failure to Vote

Coherent merger proposal:

Coherent compensation proposal:

Coherent adjournment proposal:

Virtually Attending the Coherent Special Meeting

If you wish to virtually attend the Coherent special meeting via the Coherent special meeting website, you must (i) be a Coherent stockholder of record at the close of business on May 17, 2021, (ii) hold your shares of Coherent common stock beneficially in the name of a broker, bank or other nominee as of the Coherent record date or (iii) hold a valid proxy for the Coherent special meeting.

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To enter the Coherent special meeting website and virtually attend the Coherent special meeting, you must first register at the Coherent special meeting website by visiting www.virtualshareholdermeeting.com/COHR2021SM in order to obtain a unique meeting invitation by email. If you hold your shares of Coherent common stock in street name beneficially through a broker, bank or other nominee and you wish to virtually attend and vote at the Coherent special meeting via the Coherent special meeting website, you must provide a legal proxy from your bank, broker or other nominee during registration to obtain a virtual control number. If you are unable to obtain a legal proxy from your bank, broker or other nominee, you will be able to register to attend the Coherent special meeting, but may not vote your shares at the Coherent special meeting.

If you plan to virtually attend and vote at the Coherent special meeting via the Coherent special meeting website, Coherent still encourages you to submit your voting instructions in advance by the Internet, telephone or (if you received a paper copy of the proxy materials) by mail so that your vote will be counted even if you later decide not to virtually attend the Coherent special meeting via the Coherent special meeting website. Submitting your proxy by the Internet, telephone or mail will not limit your right to virtually attend and vote at the Coherent special meeting via the Coherent special meeting website if you later decide to do so.

Proxies

A holder of shares of Coherent common stock may vote in person (virtually) or by proxy at the Coherent special meeting. If you hold your shares in your name as a holder of record, to submit a proxy, you, as a holder of Coherent shares, may use one of the following methods:

Coherent requests that holders of Coherent shares submit a proxy by telephone, over the Internet or by completing and signing the accompanying proxy card and returning it to Coherent as soon as possible in the enclosed postage-paid envelope. When the accompanying proxy card is returned properly executed, the shares represented by it will be voted at the Coherent special meeting in accordance with the instructions contained on the proxy card.

If a holder’s shares are held in “street name” by a broker, bank or other nominee, the holder should check the voting form used by that firm to determine whether the holder may submit a proxy by telephone or the Internet.

If you submit your voting instructions by proxy, regardless of the method you choose to submit your proxy, the individuals named on the enclosed proxy card, and each of them, with full power of substitution and resubstitution, will vote your shares of Coherent common stock in the way that you indicate. When completing the telephone or Internet processes or the proxy card, you may specify whether your shares of Coherent common stock should be voted “FOR” or “AGAINST” or to “ABSTAIN” from voting on all, some or none of the specific items of business to come before the Coherent special meeting.

If you properly sign your proxy card but do not mark the boxes showing how your shares of Coherent common stock should be voted on a matter, the shares of Coherent common stock represented by your properly signed proxy will be voted “FOR” the Coherent merger proposal, “FOR” the Coherent compensation proposal and “FOR” the Coherent adjournment proposal.

Every vote is important. Accordingly, you should sign, date and return the enclosed proxy card, or submit a proxy via the Internet or by telephone, whether or not you plan to attend the Coherent special meeting. Sending

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in your proxy card by mail, by telephone or on the Internet will not prevent you from voting your shares personally at the meeting because you may revoke your proxy at any time before it is voted at the meeting.

Shares Held in Street Name

If your shares of Coherent common stock are held in “street name” through a broker, bank or other nominee, you must instruct the broker, bank or other nominee on how to vote your shares. Your broker, bank or other nominee will vote your shares only if you provide specific instructions on how to vote by following the instructions provided to you by your broker, bank or other nominee.

You may not vote shares of Coherent common stock held in “street name” by returning a proxy card directly to Coherent or by voting at the Coherent special meeting unless you provide a “legal proxy” giving you the right to vote the shares, which you must obtain from your broker, bank or other nominee. If you choose to vote your shares at the Coherent special meeting, please bring proof of identification.

Further, brokers, banks or other nominees who hold shares on behalf of their customers may not give a proxy to Coherent to vote those shares with respect to any of the proposals without specific instructions from their customers, as brokers, banks, and other nominees do not have discretionary voting power on the proposals that will be voted upon at the Coherent special meeting.

Revocability of Proxies

If you are a holder of shares of Coherent common stock of record, you may revoke your proxy at any time before it is voted by:

If you hold your shares of Coherent common stock through a broker, bank or other nominee, you should contact your broker, bank or other nominee to change your vote.

Attendance at the Coherent special meeting will not in and of itself constitute revocation of a proxy. A revocation or later-dated proxy received by Coherent after the vote will not affect the vote. Coherent’s corporate secretary’s mailing address is: Coherent, Inc., 5100 Patrick Henry Drive, Santa Clara, California 95054, Attention: Corporate Secretary. If the Coherent special meeting is postponed or adjourned, it will not affect the ability of holders of Coherent common stock as of the Coherent record date to exercise their voting rights or to revoke any previously-granted proxy using the methods described above.

Adjournments and Postponements