Abstract Efficient methods have been developed for obtaining precursors of stable carbenes, viz. 5-unsubstituted 3, 4-diaryl-1, 2, 4-triazoles and 3, 3′-or 4, 4′-bridge linked bis-1, 2, 4- triazoles, by the recyclization of 5-unsubstituted 1, 3, 4-oxadiazoles or p-phenylenebis-1, 3, 4-oxadiazole with anilines or aromatic diamines in the presence of trifluoroacetic acid or with aniline hydrochlorides in pyridine.
