A solvent-free synthesis of 1-{2,4-dihydroxy-5-[3-imidazol-1-yl-3-aryl-propionyl]-3-aryl-propenones under microwave irradiation using Micheal addition of chalcones with imidazoles in the presence of glacial acetic acid as catalyst. All title compounds were screened their antibacterial activity and the compounds were elucidated on the basis of 1H NMR, IR and mass spectral data.