2,3,5,6-Tetrasubstituted-4-aryl-1-(6-ethoxybenzothiazol-2-yl)-1,4-dihydropyridines were synthesized by the reaction of 2-amino-6-ethoxybenzothiazole, an aromatic aldehyde and an active methylene compound in methanol by conventional or microwave irradiation method (solvent-free or with solid support). All compounds were tested for antibacterial and antifungal activities and the results were compared with standard drugs. Their acaricidal and antifeedant activities were also tested.