Some novel [1,2,4]triazolo[3,4‐b][1,3,4]thiadiazole derivatives were synthesized from aryl acetic acids. All the synthesized derivatives were selected for the screening of antibacterial potential against Gram‐positive bacteria [Staphylococcus aureus (MTCC 3160) and Micrococcus luteus (MTCC 1538)] and Gram‐negative bacteria [Escherichia coli (MTCC 1652) and Pseudomonas aeruginosa (MTCC 424)] and antifungal potential against Aspergillus niger (MTCC 8652) and Candida albicans (MTCC 227), and free radical scavenging activity through 2,2‐diphenyl‐2‐picrylhydrazyl hydrate method. The compounds TH‐4, TH‐13, and TH‐19 were found to be more potent antimicrobial agents compared to standard drugs. The compounds TH‐3, TH‐9, and TH‐18 also showed significant antimicrobial activity. The compound TH‐13 showed antioxidant activity with IC50 value better than the standard compound. The structures of all the synthesized compounds were confirmed by Fourier transform infrared, 1H‐NMR, liquid chromatography–mass spectrometry, and CHN analyzer.