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, 1 H 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.