Abstract The reactions of trichloromethylarenes with excess hydrazine hydrate in ethanol gives symmetrical 2, 5-diaryl-1, 3, 4-oxadiazoles in 68–96% yields. The reaction of 1, 4-bis (trichloromethyl) benzene with acylhydrazines in an ethanol-pyridine mixture gives the corresponding substituted or unsubstituted 1, 4-phenylenebis-1, 3, 4-oxadiazoles in 35– 51% yields. The mass spectra of 2, 5-diaryl-1, 3, 4-oxadiazoles and 1, 4-phenylenebis-1, 3 ...