In terms of reactivity, both aluminium and gallium silylimides are found to act as viable sources of nitride, [N] 3-. Aluminium systems react with CO to afford complexes featuring a cyanide unit (together with a silyl carboxylate moiety), while the product of the analogous reaction with a gallium silylimide also contains a cyanide ligand, in this case partnered by a siloxide group. The mechanisms for these transformations are thought to be substantially similar to that determined for the related aluminium NDipp imide (in the presence of CO), with the different ultimate products rationalized in the final mechanistic steps on the basis of the lability of the N-Si bond. Interestingly, the aluminium and gallium silylimides show more divergent reactivity towards N2O, with the gallium system alone being capable of oxide/nitride exchange to generate the azide ion, N3 -. In the aluminium analogues, the imide ([N(SiR3)]