55 ILCS 5/5-30021

The preservation commission, upon a determination after review of all evidence and information that the denial of a certificate of appropriateness has denied, or will deny the owner of a landmark or of a property within a preservation district of all reasonable use of, or return on, the property, shall undertake one or the other of the following actions: (1) offer the owner of the property reasonable financing, tax or other incentives sufficient to allow a reasonable use of, or return on, the property: (2) offer to purchase the property at a reasonable price or institute eminent domain proceedings pursuant to the Eminent Domain Act; or (3) issue a certificate of appropriateness for the proposed construction, alteration, demolition or removal.