In this study, nine novel [2-Methoxy-4-(3-alkyl/ary)-4,5-dihydro-1H-1,2,4-triazol-5-one-4-yl)-azomethinphenyl acetates (4) were synthesized by the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) with 3-methoxy-4-acetoxybenzaldehyde (3). The newly synthesized compounds were characterized using IR, 1H NMR, 13C NMR, and UV spectral data. In addition, the synthesized compounds were analyzed for their in vitro potential antioxidant activities in three different methods, including reducing power, free radical scavenging and metal chelating activity.