Diphenylketimine and trimethylaluminium form a crystalline adduct Ph2C:NH,AlMe3 which at 100° loses methane to form the azomethine derivative (Ph2C:N·AlMe2)2. In the systems Ph2C:NH–AIR3(R = Et or Ph), the 1 : 1 mixtures of the components are viscous liquids of which the infrared and proton magnetic resonance spectra provide evidence of weak complex formation. Both systems lose RH readily at 20–60° to form azomethine derivatives (Ph2C:N·AIR2)2. Features of the infrared, proton magnetic resonance, and mass spectra of the azomethine derivatives are discussed.