The reactions of ketones and C-acyl imines with Me2NCN in the presence of TiCl4 were investigated. Benzophenone and 4-methylbenzophenone react with Me2NCN to give azaoxabutadienes 4-RC6H4PhC:NCONMe2 (R = H, Me) and diazabutadienes 4-RC6H4PhC:NC(NMe2):NCONMe2 (R = H, Me). Ketones with enolizable H atoms undergo aldol reactions under these conditions. C-acyl imines OPhCCPh:NC6H4R (R = H, 4-Me, 4-Cl, 3-NO2), derived from benzil and substituted anilines, undergo [2+2] cycloaddn. with Me2NCN with subsequent ring opening to the corresponding diazabutadienes RC6H4N:C(NMe2)N:CPhCPh:NCONMe2. OPhCCPh:NCHMe2 reacts with Me2NCN to give 2-dimethylamino-1-isopropyl-4,4-diphenyl-2-imidazolin-5-one (23) in a hitherto unknown multistep reaction.