2, 6-Disubstituted-3-pyridazinones were synthesized from the reaction of trichloroethylideneacetone with substituted phenylhydrazines. From the reaction of trichloroethylideneacetone with ο-nitrophenylhydrazine, pyridazinone derivative was not obtained, but ${gamma},{gamma}$-dichloro-${gamma}$-(o-nitrophenylhydrazino)-ethylideneacetone was obtained in 24% yield