Abstract A new series of 3-(arylaminomethyl)-5-(5-methyl-1-phenyl-1H-4-pyrazolyl)-2, 3- dihydro-1, 3, 4-oxadiazole-2-thiones 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j has been synthesized by the reaction of 5-(5-methyl-1-phenyl-1H-4-pyrazolyl)-1, 3, 4-oxadiazol-2- ylhydrosulfide 5 with formaldehyde and corresponding anilines. The chemical structures of newly synthesized compounds were elucidated by IR, 1 H, 13 C-NMR, MS, and elemental ...