A series of 20 new biologically active derivatives of 2-{4, 5-(substituted diphenyl)-4H-1,2,4-triazol-3-ylthio}acetyl chloride has been synthesized, with the aim to investigate antimicrobial, free radical scavenging activity. All the synthesized compounds were characterized by spectroscopic data and elemental analysis. The final compounds were tested for antibacterial activity against Gram-positive bacteria: Staphylococcus aureus MTCC 3160, Bacillus subtilis MTCC 441; Gram-negative bacteria: Escherichia coli MTCC 443, and, for antifungal activity, against Candida albicans MTCC 227 and Aspergillus niger MTCC 281, taking ciprofloxacin as antibacterial and fluconazole as antifungal standard drugs. Compound 7a6 was found to be the most effective antibacterial (MIC = 3.12 µg/ml), and compounds 7a2 and 7d1 (MIC = 3.12 and 6.25 µg/ml) had the most effective antifungal effects on the selected strains, as compared to the standard drugs. The results of antioxidant studies revealed that compound 7b1 was found to be most active antioxidant, with 40.4±0.687 µg/ml, and compounds 7b3, 7d7, and 7d4 also showed promising free radical scavenging activity, as compared with the standard drug ascorbic acid.