Objective: The present research is aimed at the discovery and development of 1-phenyl-3-(3,4,5-trimethoxyphenyl)-1H-pyrazole derivatives as a series of novel 1, 3, 4-oxadiazoles (7a-7h) through iodine-catalyzed oxidative cyclization of the hydrazone derivatives (6a-6h) in the presence of potassium carbonate as base and DMSO as solvent in good toexcellent yields. Methods: The structures of all the newly synthesized compounds (6a-6h) and(7a-7h) were well characterized by IR, 1H NMR, 13C NMR and HRMS. Furthermore, allthe synthesized compounds (6a-6h and 7a-7h) were evaluated for their antimicrobial andanti-oxidant activities. Results: The research results revealed that the compound 6d (Z)-2-bromo-N'-((1-phenyl-3-(3, 4, 5-trimethoxyphenyl)-1H-pyrazol-4-yl) methylene) benzohydrazide) has antimicrobial potent while the synthesized compounds 6a (Z)-N'-((1-phenyl-3-(3, 4, 5-trimethoxyphenyl)-1H-pyrazol-4-yl) methylene) benzohydrazide), 6e (Z)-2, 5-dichloro-N'-((1-phenyl-3-(3, 4, 5-trimethoxyphenyl)-1H-pyrazol-4-yl) methylene) benzohydrazide), 7e (2-(2, 5-dichlorohenyl)-5-(1-phenyl-3-(3, 4, 5-trimethoxyphenyl)-1H-pyrazol-4-yl)-1, 3, 4-oxadiazole) and 7f (2-(3, 5-dichlorophenyl)-5-(1-phenyl-3-(3, 4, 5-trimethoxyphenyl)-1H-pyrazol-4-yl)-1, 3, 4-oxadiazole) exhibited strong antioxidant activity compared to the control BHT. Conclusion: The novel hydrazonessynthesized and 1, 3, 4 oxadiazole derivatives may be suggested for their establishment in chemical class of antimicrobial and antioxidant agents in new drug discovery and medicinal research.