A series of novel bis-chalcones 3a–n were synthesized in excellent yields by condensation reaction of 1,4-diacetylbenzene with various aldehydes in ethanol 96% and aqueous NaOH at room temperature. All compounds were characterized by IR, 1H and 13C NMR, UV spectroscopy and elemental analysis. The antimicrobial activities of synthesized compounds were also evaluated. The most of these compounds exhibited a good activity against Staphylococcus aureus, Escherichia coli and Candida albicans microorganisms. Some of them showed significant activities.