110 ILCS 120/1
When parks, squares or other public grounds have been legally vacated by ordinance of any municipality, and any university or college in this state, incorporated in pursuance of the laws thereof, has been hereby authorized to erect buildings for educational purposes on such vacated grounds, with a limitation in the ordinance of vacation that said grounds and the buildings erected thereon shall be used for the education of one sex, or in any other particular and limited manner, and such university or college shall have erected buildings on such vacated grounds, and when the municipality which passed the ordinance of vacation has by subsequent ordinance modified or repealed the limitation in such ordinance, or has by ordinance, or conveyance of such vacated ground to such university or college, estopped itself from insisting upon such limitation, such estoppel shall be valid against the general public to the same extent as against said municipality; and it shall be lawful for such university or college to use and control such grounds for any purpose authorized by its act of incorporation or by such subsequent ordinance or conveyance in as full and ample a manner as other grounds held by such university or college for the objects for which the same was incorporated.
110 ILCS 120/1