A new series of 4-{[2-chloro-5-(4-substitutedphenyl)pyridin-3-yl]methylene}-1- substituted-2-phenyl-1H-imidazol-5(4H)-one derivatives was synthesized by the reaction of 4-{[2-chloro-5-(4-substitutedphenyl)pyridin-3-yl)]methylidene}-2- phenyl- 1,3-oxazol-5(4H)-one with various 2-amino-benzo-thiazole and pyridine. The structures of the synthesized compounds are established with the help of TLC, IR, 1HNMR, MASS spectrometric and elemental analysis. The synthesized compounds were screened for in Vitro antibacterial activity against various bacterial strains and antifungal activity against various fungal strains.