The potassium aluminyl complex K2[Al{N(Dipp)SiMe3}2]2 was synthesised via reduction of [AlI{N(Dipp)SiMe3}2] (Dipp = 2,6-i-Pr2C6H3). 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. K2[Al{N(Dipp)SiMe3}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.