65 ILCS 125/95

The validity of a business improvement district created or amended, district plan established, or district charge imposed under this Act may not be contested in any action or proceeding unless the action or proceeding is commenced: (1) within 30 days after the formation ordinance is adopted; (2) with respect to amendments under Section 60, within 30 days after an amendment has been approved; or (3) with respect to district charges imposed under this Act, within 30 days after receipt of the bill containing the district charge. If a party appeals a final judgment, the party filing the appeal shall request discretionary acceleration under Supreme Court Rule 311(b).