The article reports the synthesis of a series comprising of twenty-one 2,5-disubstituted-4-thiazolidinone derivatives, bearing 3-chloro-4-fluorophenyl imino, 4-chlorophenyl imino and 3-chlorophenyl imino groups at position-2 and substituted arylidene groups at position-5. The title compounds were obtained in high yields through Knoevenagel condensation and evaluated for antimicrobial activity against B. subtilis, S. aureus, P. aeruginosa, E. coli, and C. albicans. Success of the synthesis was confirmed through spectral analysis. The newly synthesized compounds exhibited promising antibacterial activity but no antifungal activity. SAR studies revealed that the presence of a fluoro group in addition to a chloro group had a marked influence on the antibacterial activity.