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                                                                 EXHIBIT 5  


                                November 3, 1997


Nanophase Technologies Corporation
453 Commerce Street
Burr Ridge, Illinois  60521

      RE:  REGISTRATION STATEMENT ON FORM S-1

Ladies and Gentlemen:

     We have acted as counsel for Nanophase Technologies Corporation, an
Illinois corporation which prior to consummation of the Offering (as defined
herein) will be reincorporated in Delaware (the "Company"), in connection with
the preparation and filing of a registration statement on Form S-1 (the
"Registration Statement") with the Securities and Exchange Commission under the
Securities Act of 1933, as amended.  The Registration Statement relates to the
Company's initial public offering (the "Offering") of up to 5,750,000 shares of
the Company's common stock, $.001 par value per share (the "Common Stock"),
including the 750,000 shares of Common Stock issuable upon exercise in full of
the Underwriters' (as defined herein) over-allotment option (collectively, the
"Shares").

     In connection with this opinion, we have relied as to matters of fact,
without investigation, upon certificates of public officials and others and
upon affidavits, certificates and written statements of directors, officers and
employees of, and the accountants and transfer agent for, the Company.  We have
also examined originals or copies, certified or otherwise identified to our
satisfaction, of such instruments, documents and records as we have deemed
relevant and necessary to examine for the purpose of this opinion, including
(a) the Registration Statement, as amended, (b) the Certificate of
Incorporation of the Company, (c) the By-Laws of the Company, (d) resolutions
adopted by the Board of Directors of the Company in connection with the
Offering and (e) the form of Underwriting Agreement (the "Underwriting
Agreement") between the Company and Donaldson, Lufkin & Jenrette Securities
Corporation, Furman Selz LLC and Oppenheimer & Co., Inc., as representatives of
the several underwriters (collectively, the "Underwriters").

     In connection with this opinion, we have assumed the accuracy and
completeness of all documents and records that we have reviewed, the
genuineness of all signatures, the authenticity of the documents submitted to
us as originals and the conformity to authentic original documents of all
documents submitted to us as certified, conformed or reproduced copies.  We
have further

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Nanophase Technologies Corporation
November 3, 1997
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assumed that all natural persons involved in the Offering as contemplated by
the Registration Statement, as amended, have sufficient legal capacity to enter
into and perform their respective obligations and to carry out their roles in
the Offering.

     Based upon and subject to the foregoing, it is our opinion that the
5,750,000 Shares covered by the Registration Statement (including the 750,000
Shares issuable upon exercise in full of the Underwriters' over-allotment
option), when issued by the Company pursuant to the Underwriting Agreement,
will be validly issued, fully paid and non-assessable.

     Our opinion expressed above is limited to the General Corporation Law of
the State of Delaware and the laws of the State of New York, and we do not
express any opinion concerning any other laws.  This opinion is given as of the
date hereof and we assume no obligation to advise you of changes that may
hereafter be brought to our attention.

     We hereby consent to use of our name under the heading "Legal Matters" in
the Prospectus forming a part of the Registration Statement and to use of this
opinion for filing as Exhibit 5 to the Registration Statement.

                                     Very truly yours,

                                     /s/ KATTEN MUCHIN & ZAVIS

                                     KATTEN MUCHIN & ZAVIS