Abstract A new series of compounds 2-((1-(4-(4-arylidene-2-methyl-5-oxo-4, 5-dihydro-1 H- imidazol-1-yl) phenyl) ethylidene) hydrazono) thiazolidin-4-ones (4a–o) have been synthesized under conventional and microwave irradiation method. All compounds were characterized by IR, 1 H NMR, 13 C NMR and mass spectra. Newly synthesized compounds were screened for their antibacterial and antifungal activities on Escherichia coli, ...