A series of ten 4-(4-(dimethylamino)benzylidene)-1-(4-(3-(aryl)acryloyl) phenyl)-2-phenyl-1H-imidazol-5(4H)-ones (7) have been synthesized by condensation of 1-(4-acetylphenyl)-4-(4-(dimethylamino)benzylidene)-2-phenyl-1H-imidazol-5(4H)-one (5) with different aryl aldehydes (6). The structures of the newly synthesized compounds were characterized by FT-IR, 1 H NMR, 13 C NMR, Mass spectral studies and elemental analysis. All the above compounds were screened for their antimicrobial activity against gram positive bacteria B. subtilis, S. aureus, gram negative bacteria E. coli, P. vulgaris and the yeast C. albicans. These compounds were also tested for antioxidant activity by DPPH method and were found to be biologically active.