In this study, 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 have been reacted with 4-methoxy-3-(p-toluenesulfonyloxy)-benzaldehyde 1 to afford the corresponding nine new 3-alkykary1)-4-[4-methoxy-3-(p-toluenesulfonyloxy)benzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 4. Then, the acetylation reactions of compounds 4 have been investigated and 5 type compounds have been obtained. The structures of fifteen new compounds have been characterized by IR, H-1 and C-13 NMR, MS and UV-Vis spectral data. The synthesized compounds have been analyzed for their in vitro potential antioxidant activities by three different methods. Those antioxidant activities have been compared to standard antioxidants such as BHA, BHT and a-tocopherol. Compounds 4b, 4d and 5d show best activity for iron binding. In addition, the compounds 4 have been titrated potentiometrically with tetrabutylammonium hydroxide (TBAH) in four non-aqueous solvents. Furthermore, these fifteen new compounds have been screened for their antimicrobial activities.