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SECOND AMENDED AND RESTATED SHAREHOLDERS’ AGREEMENT

SECOND AMENDED AND RESTATED SHAREHOLDERS’ AGREEMENT, dated as of January 18, 2005, by and among Celanese Corporation, a Delaware corporation (formerly known as Blackstone Crystal Holdings Capital Partners (Cayman) IV Ltd.) (the “ Company ”), Blackstone Capital Partners (Cayman) Ltd. 1 (“ BCP 1 ”), Blackstone Capital Partners (Cayman) Ltd. 2 (“ BCP 2 ”), Blackstone Capital Partners (Cayman) Ltd. 3 (“ BCP 3 ” and, together with BCP 1 and BCP 2 and their respective successors and Permitted Assigns (as hereinafter defined), the “ Blackstone Entities ”), each an exempted company incorporated under the laws of the Cayman Islands, and BA Capital Investors Sidecar Fund, L.P., a Cayman Islands limited partnership (together with its successors and Permitted Assigns, “ BACI ”).  Each of the Blackstone Entities and BACI and their respective successors and Permitted Assigns are sometimes referred to individually as a “ Shareholder ” and together as the “ Shareholders .”

BACKGROUND:

WHEREAS, in connection with the consummation of the voluntary public takeover offer by a subsidiary of the Company for all of the outstanding registered ordinary shares of Celanese AG (the “ Offer ”), the Blackstone Entities and BACI acquired ordinary shares, par value $0.01 per share, of the Company (the “ Ordinary Shares ”);

WHEREAS, the Blackstone Entities and BACI entered into the Shareholders’ Agreement, dated as of April 6, 2004 (as subsequently amended and restated as of November 1, 2004, the “ Original Agreement ”) to provide for certain matters relating to their respective holdings of Ordinary Shares and the governance of the Company;

WHEREAS, on November 3, 2004, the Company migrated from the Cayman Islands to the State of Delaware, redomiciled itself as a Delaware corporation and changed its name from “Blackstone Crystal Holdings Capital Partners (Cayman) IV Ltd.” to “Celanese Corporation”;

WHEREAS, in connection with, and effective upon, the Initial Public Offering (as defined in Section 1.1) of the Company, and in accordance with Section 6.7 of the Original Agreement, the parties to the Original Agreement wish to amend and restate the Original Agreement in its entirety in order to set forth certain understandings regarding the governance of the Company and the relationship among the Company and the Shareholders following consummation of the Initial Public Offering;

NOW, THEREFORE, the parties agree as follows:

ARTICLE I .                   INTRODUCTORY MATTERS

11.1    Defined Terms .  In addition to the terms defined elsewhere herein, the following terms have the following meanings when used herein with initial capital letters:

“ Affiliate ” means, with respect to any Person, (i) any Person that directly or indirectly controls, is controlled by or is under common control with, such Person or (ii) any director, officer, member, partner (including limited partners) or employee of

such Person or any Person specified in clause (i) above; provided that officers, directors or employees of the Company will be deemed not to be Affiliates of the Shareholders for purposes hereof solely by reason of being officers, directors or employees of the Company.

“ Agreement ” means this Second Amended and Restated Shareholders’ Agreement, as the same may be amended, supplemented, restated or otherwise modified from time to time in accordance with the terms hereof.

“ Assumption Agreement ” means a writing reasonably satisfactory in form and substance to the Blackstone Entities whereby a BACI Affiliate Transferee becomes a party to, and agrees to be bound to the same extent as its transferor, by the terms of this Agreement.

“ BACI ” has the meaning set forth in the preamble.

“ BACI Affiliate Transferee ” has the meaning set forth in Section 2.2.

“ BACI Permitted Assign Agreement ” means an agreement reasonably satisfactory in form and substance to the Blackstone Entities whereby such Transferee agrees that it shall be bound by all of the provisions of this Agreement as if it were BACI, but shall not be entitled to the benefits of Article III hereof.

“ BCP 1 ” has the meaning set forth in the preamble.

“ BCP 2 ” has the meaning set forth in the preamble.

“ BCP 3 ” has the meaning set forth in the preamble.

“ Blackstone Entities ” has the meaning set forth in the preamble.

“ Blackstone Intervening Entity ” means BCP 1, BCP 2, BCP 3 and any other Person created by Blackstone Capital Partners (Cayman) IV L.P., Blackstone Capital Partners (Cayman) IV-A L.P., Blackstone Family Investment Partnership (Cayman) IV-A L.P. or Blackstone Chemical Coinvest Partners Cayman L.P. (collectively, the “ Blackstone Funds ”), but excluding the Blackstone Funds themselves, formed for the purpose of making the investment, directly or indirectly, in the Company.

“ Blackstone Representative ” means the Blackstone Entity designated from time to time by all of the Blackstone Entities to serve as the representative of the Blackstone Entities for certain purposes hereunder.

“ Board ” means the board of directors of the Company.

“ Business Day ” means a day other than a Saturday, Sunday, federal or New York State holiday or other day on which commercial banks in New York City are authorized or required by law to close.

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“ Certificate of Incorporation ” means the amended and restated certificate of incorporation of the Company, as the same may be amended, supplemented, restated or otherwise modified from time to time in accordance with the terms hereof.

“ Company ” has the meaning set forth in the preamble.

“ Common Stock ” means the shares of Series A common stock and Series B common stock, par value $0.0001 per share, of the Company, and any other capital stock of the Company into which such stock is reclassified or reconstituted and any other common stock of the Company.

“ Common Stock Equivalents ” means any security or obligation which is by its terms convertible, exchangeable or exercisable into or for shares of Common Stock, whether at the time of issuance or upon the passage of time or the occurrence of some future event.

“ Director ” means any member of the Board.

“ Drag-Along Buyer ” has the meaning set forth in Section 2.5(a).

“ Drag-Along Notice ” has the meaning set forth in Section 2.5(b).

“ Drag-Along Shareholders ” shall have the meaning as set forth in Section 2.5(a).

“ Exchange Act ” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder, as the same may be amended from time to time.

“ Initial Public Offering ” means the closing of the first sale of shares of Series A Common Stock of the Company to the public pursuant to an effective registration statement (other than a registration statement on Form S-4 or S-8 or any similar or successor form) filed under the Securities Act.

“ Initial Share Holding Period ” has the meaning set forth in Section 2.1(a).

“ Majority Shareholders ” has the meaning set forth in Section 2.5(a).

“ Offer ” has the meaning set forth in the preamble.

“ Offer Notice ” has the meaning set forth in Section 2.3(a).

“ Offer Period ” has the meaning set forth in Section 2.3(a).

“ Permitted Assigns ” means (i) with respect to any Blackstone Entity, a Transferee of shares of Common Stock of such Blackstone Entity that agrees to become party to, and to be bound to the same extent as its transferor by the terms of, this Agreement and (ii) with respect to BACI, a BACI Affiliate Transferee or a Transferee of shares of

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Common Stock of BACI that executes and delivers to the Company and each Blackstone Entity a BACI Permitted Assign Agreement.

“ Person ” means any individual, corporation, limited liability company, partnership, trust, joint stock company, business trust, unincorporated association, joint venture, governmental authority or other legal entity of any nature whatsoever.

“ Preferred Stock ” means the shares of preferred stock, par value $0.01 per share, of the Company and any other capital stock of the Company into which such stock is designated, reclassified or reconstituted, and any other preferred stock of the Company.

“ Proposed Sale ” has the meaning set forth in Section 2.4(a).

“ Proposed Transferee ” has the meaning set forth in Section 2.4(a).

“ Public Offering ” means a sale of common equity or equivalent securities of the Company to the public pursuant to an effective registration statement (other than a registration statement on Form S-4 or S-8 or any similar or successor form) filed under the Securities Act.

“ Registration Rights Agreement ” means the Amended and Restated Registration Rights Agreement dated as of the date hereof among the Company and the Shareholders, as such agreement may be amended, supplemented or otherwise modified from time to time.

“ Related Persons ” has the meaning set forth in Section 4.4.

“ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder, as the same may be amended from time to time.

“ Shareholder ” or “ Shareholders ” has the meaning set forth in the preamble.

“ Tag-Along Notice ” has the meaning set forth in Section 2.4(b).

“ Tagging Shareholder ” has the meaning set forth in Section 2.4(a).

“ Tender Offer Closing ” means the closing of the first acquisition of registered ordinary shares of Celanese AG by BCP Crystal Acquisition GmbH & Co. KG pursuant to its voluntary public takeover offer published February 2, 2004.

“ Transfer ” means a transfer, sale, assignment, pledge, hypothecation or other disposition, whether directly or indirectly pursuant to the creation of a derivative security, the grant of an option or other right, the imposition of a restriction on disposition or voting or transfer by operation of law.  When used as a verb, “Transfer” shall have the correlative meaning.  In addition, “Transferred” and “Transferee” shall have the correlative meanings.

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1.2    Construction .  The language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rule of strict construction will be applied against any party.  Unless the context otherwise requires:  (a) ” or ” is disjunctive but not exclusive, (b) words in the singular include the plural, and in the plural include the singular, and (c) the words “ hereof ”, “ herein ”, and “ hereunder ” and words of similar import when used in this Agreement refer to this Agreement as a whole and not to any particular provision of this Agreement, and Section references are to this Agreement unless otherwise specified.

ARTICLE II .                  TRANSFERS

2.1    Limitations on Transfer .  (a)  Without the prior written consent of the Blackstone Representative, BACI may not Transfer any shares of Common Stock prior to the six (6) month anniversary of the Initial Public Offering (or such shorter period as the underwriters for such Initial Public Offering shall require of either the Blackstone Entities or BACI) (the “ Initial Share Holding Period ”) other than (1) to a BACI Affiliate Transferee in accordance with the provisions of Section 2.2, (2) to one or more Blackstone Entities pursuant to Section 2.3, (3) as a Tagging Shareholder pursuant to Section 2.4, (4) as a Drag-Along Shareholder pursuant to Section 2.5 or (5) pursuant to the rights set forth in the Registration Rights Agreement.  Without limiting BACI’s rights to transfer to a BACI Affiliate Transferee pursuant to clause (1) of the preceding sentence, in the event of any proposed Transfer by BACI of all of the shares of Common Stock held by BACI to a Transferee that is an institutional investor of national reputation and that executes a BACI Permitted Assign Agreement, which proposed Transfer is subject to the rights set forth in Section 2.3 below, such consent of the Blackstone Representative shall not be unreasonably withheld or delayed.  After the Initial Share Holding Period, BACI may Transfer its shares of Common Stock only in accordance with, and subject to the applicable provisions of, this Article II or pursuant to the rights set forth in the Registration Rights Agreement.  Any Transferee of BACI prior to the expiration of the Initial Share Holding Period must qualify as a Permitted Assign of BACI.

(b)           In the event of any purported Transfer by BACI of any shares of Common Stock in violation of the provisions of this Agreement, such purported Transfer will be void and of no effect and the Company will not give effect to such Transfer.

(c)           Each certificate representing shares of Common Stock held by any Shareholder will bear a legend substantially to the following effect:

“THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A SHAREHOLDERS’ AGREEMENT AMONG CELANESE CORPORATION AND THE SHAREHOLDERS PARTY THERETO, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF CELANESE CORPORATION.  THE SHAREHOLDERS’ AGREEMENT CONTAINS, AMONG OTHER THINGS, CERTAIN PROVISIONS RELATING TO THE TRANSFER OF THE SHARES SUBJECT TO THE AGREEMENT.  NO TRANSFER, SALE, ASSIGNMENT, PLEDGE, HYPOTHECATION OR OTHER DISPOSITION OF THE SECURITIES REPRESENTED BY THIS CERTIFICATE MAY, DIRECTLY OR INDIRECTLY, BE MADE EXCEPT IN ACCORDANCE WITH THE PROVISIONS OF SUCH

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SHAREHOLDERS’ AGREEMENT.  THE HOLDER OF THIS CERTIFICATE, BY ACCEPTANCE OF THIS CERTIFICATE, AGREES TO BE BOUND BY ALL OF THE PROVISIONS OF SUCH SHAREHOLDERS’ AGREEMENT.

THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE TRANSFERRED OR OTHERWISE DISPOSED OF UNLESS THEY HAVE BEEN REGISTERED UNDER THAT ACT OR AN EXEMPTION FROM REGISTRATION IS AVAILABLE.”

This legend will be removed by the Company, with respect to any certificate representing shares of Common Stock, by the delivery of substitute certificates without such legend in the event of (i) a Transfer permitted or not prohibited by this Agreement and in which the Transferee is not required to, pursuant to this Article II, enter into an Assumption Agreement or a BACI Permitted Assign Agreement or (ii) the termination of this Agreement pursuant to the terms hereof, provided , however , that the second paragraph of such legend will only be removed if at such time it is no longer required for purposes of applicable securities laws.

(d)           Any Transfer by a Shareholder permitted under this Agreement shall be effective only upon receipt by the Company of information reasonably satisfactory to it, demonstrating that such Transfer is exempt from or not subject to the provisions of Section 5 of the Securities Act and any other applicable securities laws (for such purpose, an opinion of Kirkland & Ellis LLP, or other counsel reasonably acceptable to the Company, to that effect shall constitute such reasonably satisfactory information), provided that no such Transfer shall be permitted, except as permitted under the Registration Rights Agreement, if such Transfer would require the Company to register a class of equity securities under Section 12 of the Exchange Act under circumstances where the Company does not then have securities of any class registered under Section 12 of the Exchange Act and such Transfer would cause such registration to be required.

2.2    Transfers to BACI Affiliate Transferees .  BACI may, at any time, Transfer shares of Common Stock, subject to compliance with the other provisions of this Agreement, to an Affiliate of Bank of America Corporation who duly executes and delivers to the Company and each Blackstone Entity an Assumption Agreement (a “ BACI Affiliate Transferee ”); provided , however , that in the event a transaction or event is contemplated in which any BACI Affiliate Transferee to which shares of Common Stock are Transferred will cease to qualify as a BACI Affiliate Transferee, other than in connection with the bona fide sale or other disposition by Bank of America Corporation, or any of its Affiliates, of a business unit that includes such BACI Affiliate Transferee, such BACI Affiliate Transferee to which shares of Common Stock are Transferred shall, and BACI shall cause such BACI Affiliate Transferee to: (a) promptly notify the Company of the pending occurrence of such transaction or event; and (b) prior to the time such BACI Affiliate Transferee ceases to be a BACI Affiliate Transferee, Transfer back to BA Capital Investors Sidecar Fund, L.P. (or to another BACI Affiliate Transferee) any shares of Common Stock it owns and such Transferee will execute and deliver an Assumption Agreement with respect thereto.

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2.3    Right of First Refusal .  (a)  If at any time prior to the expiration of the Initial Share Holding Period, BACI proposes to Transfer, all or any portion of the shares of Common Stock held by it (other than (i) to a BACI Affiliate Transferee in accordance with Section 2.2, (ii) as a Tagging Shareholder pursuant to Section 2.4, (iii) as a Drag-Along Shareholder pursuant to Section 2.5 or (iv) pursuant to the rights set forth in the Registration Rights Agreement) and BACI has received a bona fide arm’s length offer for the shares of Common Stock subject to such Transfer, BACI shall deliver to the Blackstone Representative a written notice (the “ Offer Notice ”) of such proposed transaction, which shall identify the proposed Transferee and set forth the proposed terms of such Transfer, including the number of shares of Common Stock proposed to be Transferred and the purchase price therefor.  The Offer Notice shall contain an irrevocable offer to sell to the Blackstone Entities the shares of Common Stock proposed to be Transferred at a price equal or equivalent (as determined in the manner set forth below) to the price contained in, and otherwise on the same terms and conditions of, the Offer Notice.  The Blackstone Entities shall have fifteen (15) Business Days from the date the Offer Notice is received (the “ Offer Period ”) to determine whether one or more of such Blackstone Entities, or one or more of their designees, shall exercise the right to purchase all (but not less than all) of the shares of Common Stock subject to the Offer Notice on the terms set forth in such Offer Notice, provided , however , that if the proposed transaction includes any consideration other than cash, then, at the sole option of any such Blackstone Entity or designee, the relevant price shall be the equivalent cash price, determined (x) in the case of consideration consisting of securities listed or quoted on a national securities exchange or the Nasdaq National Market System, by the average daily closing sales price, as reported by Bloomberg L.P. (or if not reported by Bloomberg L.P., as reported by a reporting service of similar national reputation), of such securities on their principal trading market for the ten consecutive trading days preceding the date of receipt of the Offer Notice and (y) in the case of any other non-cash consideration, by the Board, acting reasonably and in good faith.  If a Blackstone Entity does not respond to the Offer Notice within the Offer Period, then such Blackstone Entity will be deemed to have elected not to exercise the right of first refusal specified in the Offer Notice.

If one or more of the Blackstone Entities and/or their respective designees shall have agreed to purchase shares of Common Stock pursuant to this Section 2.3, the applicable Blackstone Entities and/or their designees shall consummate such purchase by delivering, against receipt of certificates or other instruments representing the shares of Common Stock being purchased, appropriately endorsed by BACI, the purchase price for such shares.  Such closing date will be the later of (i) fifteen (15) Business Days after the expiration of the Offer Period and (ii) five (5) Business Days after receipt of all governmental consents and approvals, and the expiration of all governmental waiting periods, required for such Transfer.  BACI shall give participating Blackstone Entities and/or designees at least five (5) Business Days written notice of the closing date.

(b)           If none of the Blackstone Entities exercises its right of first refusal under Section 2.3(a), then BACI shall be permitted to Transfer the shares of Common Stock subject to the Offer Notice, no later than sixty (60) days after the expiration of the Offer Period at a price not less than the purchase price per share set forth in the Offer Notice and on other terms not materially less favorable to BACI than those terms set forth in the Offer Notice.  If BACI does not Transfer the shares of Common Stock in the time period provided for in this Section 2.3(b),

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any Transfer by BACI of any such shares after such period shall again be subject to this Section 2.3.

2.4    Tag-Along Rights .  (a)  Until the expiration of the Initial Share Holding Period, if any Blackstone Entity (a “ Selling Shareholder ”) proposes to Transfer shares of Common Stock, which Transfer or series of related Transfers relates to more than 5% of the then-outstanding shares of Common Stock (other than (i) to an Affiliate that qualifies as a Permitted Assign or (ii) pursuant to the exercise of rights set forth in Section 2.5 or in the Registration Rights Agreement) (any such transaction, a “ Proposed Sale ”), then each of the other Shareholders that is not a Blackstone Entity will have the right to require the proposed Transferee (a “ Proposed Transferee ”) to purchase from any such other Shareholder who exercises its rights pursuant to this Section 2.4 (