Monoanionic iminophosphonamide ligands have a N-P-N linkage and undergo four-membered ring N,N-ligand formation when treated with aluminum compounds. The reaction of LLi (L = [Ph2P(NSiMe3)(2)]) with equivalent amounts of AlCl3 and AlMeCl2 in toluene afforded LAlCl2 (3) and LAlClMe (4), respectively, L2AlH (5), LAlEt2 (6), and LAl(NMe2)(2) (7) respectively were prepared by the reaction of LH with AlH3 center dot NMe3, AlEt3, and Al(NMe2)(3) in n-hexane. Subsequently compounds 3-7 were characterized by elemental analysis, H-1, C-13, and P-31 NMR spectroscopy and X-ray crystallographic studies (for 3, 4, 5, and 7).