in Wiley Online Library (wileyonlinelibrary.com).Gas-phase pyrolysis of N-arylidine-N′-pyrimidin-2-yl-hydrazine derivatives 1a-e gave the corresponding arylnitriles 2a-e, 2-aminopyrimidine 3, 3-phenyl-1,2,4-triazolo[4,3-a]pyrimidines 4, 2-phenyl-1,2,4-triazolo [1,5-a]pyrimidines 5, 2,4,5-triphenyl-1H-imidazole 6, and 2,3-diphenylquinoline 7. The analyses of the reaction products are reported and used to elucidate the mechanism of the pyrolytic process.