Well, if you are living in Chicago, take them to Chicago Downtown to Macy's, Water Tower, John Hancock or Drake Hotel. They all have nice shopping place and restaurants too. I think your parents prefer to shop more that eating in restaurants. Take them and see what they like and go to any restaurants on Michigan Ave. Nice area too.
My cousins from Poland prefer to go Chicago Downtown shopping. They like Millieumen Park very much.
For a taste of Chicago....take them one night to Little Italy, any Taylor Street restaurant will work (look at Metromix). Another night, a visit to China Town. For just a drink....wrigleyville or Trumps 17th floor. A nice wine bar/restaurant, hit Enetoca on Division (U Village / Wicker Park). Don't forget to get some Meixcan food in...perhaps Lalos, or a small tacoria for lunch...
There is lot of place in Chicago Surburban too. Go to Woodfield Mall, Old Orchard Mall and Golf Mills Mall which you will find lot of Polish People in Golf Mills. There Is Long Trees Inns not far from Golf Mills.
And also there are lot of Polish People living in Algonquin too. Nice Area to visit. You can go to Spring Hills Mall in Carpenterville, IL. Nice and friendly place too. You can take your parents to Long Grove, IL. Beautiful place to visit.