Abstract A novel series of 2-(5-methyl-1, 3-diphenyl-1H-pyrazol-4-yl)-5-phenyl-1, 3, 4- oxadiazoles 7 (a–m) were synthesized either by cyclization of N′-benzoyl-5-methyl-1, 3- diphenyl-1H-pyrazole-4-carbohydrazide 4a using POCl 3 at 120 C or by oxidative cyclization of hydrazones derived from various arylaldehyde and (E)-N′-benzylidene-5- methyl-1, 3-diphenyl-1H-pyrazole-4-carbohydrazide 5 (a–d) using chloramine-T as ...