Given the ability of both aluminium and gallium silylimides to convert CO to cyanide, we wanted to examine the reactivity of these systems towards N2O, hypothesizing that a further example of O/N -metathesis might lead to the generation of azide, N3 -. In the event, the reactivity displayed diverges more markedly between the aluminium and gallium silylimides. When aluminium imides K[1a], K[1b] or K[1c] are exposed to an atmosphere of N2O, clean conversion is observed within 10 min to yield the previously reported