The reactivity of the reduced heterobimetallic complex Zr((PrNPPr2)-Pr-i-Pr-i)(3)CoN2 (1) toward aryl azides was examined, revealing a four-electron redox transformation to afford unusual heterobimetallic zirconium/cobalt diimido complexes. In the case of p-tolyl azide, the diamagnetic C-3-symmetric bis(terminal imido) complex 3 is formed, but mesityl azide instead leads to asymmetric complex 4 featuring a bridging imido fragment.