The first reported sodium alkyl(TMP)aluminate reagent to be synthesised and crystallographically characterised, [TMEDA.Na(mu-TMP)(mu-(I)Bu)Al((I)Bu)2], reacts as an amido base towards phenylacetylene to form crystalline [(TMEDA)2.Na(mu-CCPh)(mu-(I)Bu)Al((I)Bu)2]; whereas the congeneric TMEDA-stabilised lithium (TMP)aluminate exhibits dual alkyl/amido basicity in its reaction with N,N-diisopropylbenzamide to form a novel heterobimetallic-heterotrianionic crystalline complex [{PhC(=O)N(iPr)2}.Li{2-[1-C(=O)N(iPr)2]C6H4}{Me2NCH2CH2N(Me)CH2}Al(iBu)2], which, in addition to having an ortho-deprotonated benzamide ligand, also contains a methyl-deprotonated TMEDA ligand and a neutral benzamide molecule ligated to lithium.