Well, I'm a Chicagoan, but I don't smoke and I don't spend enough time in bars, but I think this is the answer:
According to the Chicago Indoor Clean Air Ordinance of 2005 (effective January 16, 2006), freestanding bars/taverns (establishments that derive 65% or more of their sales receipts from alcohol) can permit smoking, but it's up to the establishment. Likewise, restaurants with attached bars can permit smoking within 15 feet of the actual bar, as long as the dining section is suitably smoke free. Bottom line -- if you're in a bar/club where you would expect people to be smoking, they probably will be.
Smoke'em while you got'em, because on January 1, 2008 the State of Illinois bans smoking in virtually all public places.
Hope you enjoy your visit.