Legal Question in Civil Rights Law in Illinois

Very possibly if it was worded properly. If you have a job opportunity, however, you have a choice: take the job and risk a possible legal action if your former employer considers it a violation of the contract, or tell your former employer if YOU think it will be a violation but get a "waiver" of the provision and then have clear sailing. There are risks either way; you should have an attorney look at the contract if you never did before as that may help a lot determine which course of action would be more appropriate.