4–Thiazolidinones of type 3a–m and 4a–m have been prepared by the cyclocondensation of azomethines of type 2a–m with thioglycolic acid and thiolactic acid respectively. The reactions of 2–chloro–6–methylquinoline–3–carboxaldehyde with arylamines have furnished the azomethines 2a–m. The products were evaluated for their in vitro growth inhibiting activity against several microbes. Some of the compounds showed significant antimicrobial activity.