Sec Form 4 Filing - BLACKSTONE MANAGEMENT ASSOCIATES CAYMAN IV LP @ Celanese CORP - 2007-05-18

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person BLACKSTONE MANAGEMENT ASSOCIATES CAYMAN IV LP 2. Issuer Name and Ticker or Trading Symbol Celanese CORP [ CE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) X __ Other (specify below) See Remarks (Last) (First) (Middle) C/O THE BLACKSTONE GROUP, 345 PARK AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 05/18/2007 (Street) NEW YORK, NY10154 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Series A common stock, par value $0.0001 per share 05/18/2007 S( 8 ) 13,647,620 D $ 35.5 0 I See footnotes ( 1 ) ( 2 ) ( 3 ) ( 5 ) ( 6 ) ( 7 ) Series A common stock, par value $0.0001 per share 05/18/2007 S( 8 ) 946,501 D $ 35.5 0 I See footnotes ( 1 ) ( 2 ) ( 3 ) ( 5 ) ( 6 ) ( 7 ) Series A common stock, par value $0.0001 per share 05/18/2007 S( 8 ) 7,420,144 D $ 35.5 0 I See footnotes ( 1 ) ( 2 ) ( 3 ) ( 5 ) ( 6 ) ( 7 ) Series A common stock, par value $0.0001 per share 05/18/2007 S( 8 ) 92,332 D $ 35.5 0 I See footnotes ( 4 ) ( 5 ) ( 6 ) ( 7 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BLACKSTONE MANAGEMENT ASSOCIATES CAYMAN IV LP C/O THE BLACKSTONE GROUP 345 PARK AVENUE NEW YORK, NY10154 X See Remarks BLACKSTONE CAPITAL PARTNERS CAYMAN IV LP BLACKSTONE GROUP 345 PARK AVE NEW YORK, NY10154 X BLACKSTONE FAMILY INVESTMENT PARTNERSHIP CAYMAN IV-A LP BLACKSTONE GROUP 345 PARK AVE NEW YORK, NY10154 X BLACKSTONE CAPITAL PARTNERS CAYMAN IV- A LP BLACKSTONE GROUP 345 PARK AVE NEW YORK, NY10154 X Blackstone Chemical Coinvest Partners (Cayman) L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Management Partners IV L.L.C. 345 PARK AVENUE NEW YORK, NY10154 Other Signatures /s/ Robert L. Friedman 05/18/2007 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Blackstone Capital Partners (Cayman) Ltd. 1 ("Cayman 1"), Blackstone Capital Partners (Cayman) Ltd. 2 ("Cayman 2"), and Blackstone Capital Partners (Cayman) Ltd. 3 ("Cayman 3" and, collectively with Cayman 1 and Cayman 2, the "Cayman Entities"), respectively owned 13,647,620, 946,501 and 7,420,144 shares of the Series A common stock previously reported as beneficially owned. Blackstone Capital Partners (Cayman) IV L.P. ("BCP IV") owns 100% of Cayman 1. Blackstone Family Investment Partnership (Cayman) IV-A L.P. ("BFIP") and Blackstone Capital Partners (Cayman) 1V-A L.P. ("BCP IV-A") collectively own 100% of Cayman 2. Blackstone Chemical Coinvest Partners (Cayman) L.P. ("BCCP" and, collectively with BCP IV, BFIP and BCP IV-A, the "Blackstone Funds") owns 100% of Cayman 3. ( 2 )Each of the Blackstone Funds may have been deemed to be the beneficial owner of the shares of Series A common stock held by the Cayman Entities owned by such Blackstone Funds. Blackstone Management Associates (Cayman) IV L.P. ("BMA") is the general partner of each of the Blackstone Funds and, therefore, may also be deemed to have been the beneficial owner of the shares of Series A common stock held by the Cayman Entities. Blackstone LR Associates (Cayman) IV Ltd. ("BLRA") is the general partner of BMA and may also, therefore, have been deemed to be the beneficial owner of the shares of Series A common stock held by the Cayman Entities. ( 3 )Messrs. Peter G. Peterson and Stephen A. Schwarzman are directors and controlling persons of BLRA and, as such, may have been deemed to share beneficial ownership of the shares of Series A common stock held by the Cayman Entities. ( 4 )Blackstone Management Partners IV, L.L.C. ("BMP") owned 92,332 shares of Series A common stock previously reported as beneficially owned. Messrs. Peter G. Peterson and Stephen A. Schwarzman are controlling members of BMP and, as such, may have been deemed to share beneficial ownership of the shares of Series A common stock held by BMP. ( 5 )Due to the electronic system's limitation of 10 Reporting Persons per joint filing, this statement is being filed in duplicate. ( 6 )Information with respect to each of the Reporting Persons is given solely by such Reporting Persons, and no Reporting Person has responsibility for the accuracy or completeness of information supplied by another Reporting Person. ( 7 )Pursuant to Rule 16a-1(a)(4) of the Exchange Act, each of the Reporting Persons, other than the Cayman Entities and BMP, herein states that this filing shall not be deemed an admission that he or it was the beneficial owner of any of the shares of Series A common stock covered by this Statement. Each of BLRA, BMA and Messrs. Peter G. Peterson and Stephen A. Schwarzman disclaims beneficial ownership of the Series A common stock, except to the extent of its or his pecuniary interest in such shares of Series A common stock. ( 8 )The shares of the Series A common stock reported as disposed of in the above table were sold in a secondary offering of the Issuer's Series A common stock pursuant to an Underwriting Agreement, dated May 14, 2007.

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