A facile heterogeneous synthesis of 1,4-dihydropyridine was effectively conducted using one-pot three component-coupling of an aromatic aldehyde, an active methylene substance, and ammonium acetate in the presence of nanochitosan as a biopolymer catalytic system under solvent-free microwave-irradiation conditions in satisfactory yields. Chitosan nanocatalyst with a minimum particle size of < 100 nm was synthesized by crosslinking low molecular weight chitosan with polyanion sodium tripolyphosphate and physicochemically analyzed. The products of Hantzsch reaction obtained were determined by FTIR, UV/Vis spectrophotometer, and mass analysis. The antioxidant properties of the compounds were analyzed using DPPH method. The present method offers several advantages including easy isolation of products, easier work-up procedure, green conditions, excellent yields and short reaction time.