The syntheses of 1,3-diarylpyrazino[1,2-a]benzimidazole derivatives and the investigation of their anticancer activities were studied. For this, 2-aryloylbenzimidazole derivatives were reacted with 2-bromoacetophenones in acetone to give 1-(2-aryl-2-oxoethyl)-2-aryloylbenzimidazoles. The resulting materials were reacted with ammonium acetate in acetic acid to obtain the aimed compound. In this reaction, microwave irradiation method was applied as the reaction conditions. Anticancer activities of the compounds obtained were investigated. It was observed that some of the compounds showed remarkable anticancer activities.