Salt metathesis, i.e. the reaction of sodium β-diketiminate with (AlCp*)₄ and GaCp*, respectively, is a valuable pathway to access the respective aluminium(I) and gallium(I) β-diketiminates I and II. The protocol gives better yields compared to the established procedures and avoids the use of strong reducing agents such as metallic potassium. Furthermore, the aluminium(I) β-diketiminate I was found to react with itself and yields upon C–N bond cleavage and hydrogen-atom transfer the asymmetric dinuclear aluminium(III) complex V that is readily separated from I by crystallisation. The reaction mechanism has been probed by means of DFT and DLPNO-CCSD(T) calculations and the computational findings are in good agreement with the experimental observations.