A synthesis of 3,5-disubstituted-1,2,4-triazoles from nitriles and 5-aryltetrazoles is reported. When 5-aryltetrazoles are triflylated in the presence of nitriles, the resulting 5-aryl-2-triflyltetrazoles thermally generate N-triflyl-nitrile imines through a sequence of ring-chain tautomerization and denitrogenation. The N-triflyl-nitrile imines immediately undergo 1,3dipolar cycloaddition with nitriles in a regioselective manner, forming the corresponding 1,2,4-triazoles.