The IRS has clarified which returns can be filed July 15. Only corporate and individual returns due April 15 can be filed on July 15. If your return is due May 15 or June 15, you need to file for an extension of time.
Illinois corporate and individual income tax returns due April 15 can be filed and tax paid on July 15. However, estimated payments due on April 15 or June 15 must be paid on April 15 or June 15. Penalties will begin to accumulate if not paid on time.
Illinois nonprofits must still file their IRS form 990 by May 15 or June 15, as appropriate, or ask for an extension of time. In addition, the AG-990 must still be filed by June 30. If you need an extension of time, you need to request an extension of time. They will normally give you a 60-day extension of time.