8 Pieces 3-alkyl(aryl)-4-(3-methoxy-4-hydroxybenzylideneamino)-4,5-dihydro-1H-1,2,4-triazol-5-one (3) compounds have been obtained from reacting with 3-methoxy-4-hydroxybenzaldehyde (2) of 3-Alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-one (1) compounds. Synthesized compounds have been obtained 8 pieces 1-(morpholin-4-yl-methyl)-3-alkyl(aryl)-4-(3-methoxy-4-hydroxybenzylideneamino)-4,5-dihydro-1H-1,2,4-triazol-5-one (4) compounds from reaciton with morpholine and 7 pieces 1-(4-piperidinecarboxamide-1-yl-methyl)-3-alkyl(aryl)-4-(3-methoxy-4-hydroxybenzylideneamino)-4,5-dihydro-1H-1,2,4-triazol-5-one (5) compounds from reaciton with 4-piperidinecarboxamide ın formaldehyde environment, based on the Mannich reaction. IR, 13C NMR and 1H NMR spectroscopy methods have been utilized to analyze the structures of obtained 15 molecules. Additionally, the in-vitro antioxidant properties of the obtained potentially biologically active Mannich bases have been examined using, metal chelate activity, reducing power methods and free radical scavenging activity, and the outcomes obtained have been contrasted with the standard antioxidant compounds used. The final section of the study examined the invitro antimicrobial effects of the synthesized molecules in opposition to six distinct microorganisms (Bacillus cereus, Bacillius Subtilis, Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli, and Staphylococcus aureus) utilizing the Agar Well Technique. Those findings were assessed.