The potassium aluminyl complex K 2 Al{N(Dipp)SiMe 3 } 2 2 was synthesised via reduction of AlI{N(Dipp)SiMe 3 } 2 (Dipp = 2,6-i-Pr 2 C 6 H 3 ). This represents the first example of an aluminyl anion supported by an acyclic ligand framework. Attempts to yield the same structure with a larger ligand framework, {N(Dipp)Si(i-Pr) 3 }, led to C-H cleavage. K 2 Al{N(Dipp)SiMe 3 } 2 2 behaves as a nucleophilic source of aluminium; reaction with an electrophilic β-diketiminate supported magnesium( ii ) iodide forms a monomeric, acyclic magnesium aluminyl complex. The potassium aluminyl, K 2 Al{N(Dipp)SiMe 3 } 2 2 has been synthesised. Reaction with HC{(CH 3 )C(Dipp)N} 2 MgI(OEt 2 ) forms HC{(CH 3 )C(Dipp)N} 2 MgAl{N(Dipp)SiMe 3 } 2 , a monomeric, acyclic, magnesium aluminyl complex.