The mechanochemical synthesis of tertiary and secondary alanes AlR3 (R = Np 1 or Mes 2; HAlR2 R = Np 3 or Mes 4) is described. These species are reacted with several α-diimines to give a series of aluminium-derived radicals of the form [(diimine)AlR2]˙ (6–11). EPR and several crystallographic studies are reported. These species are thought to form via hydro- or carboalumination and subsequent elimination reactions. This view is supported by the structural data for minor products C12H7(NHDipp)(NDipp)AliBu25 and C13H8(C(iBu)N(m-Xy)(NH(m-Xy)))AliBu212. In addition, the characterization of (C6F5)2B(OC(C6F5)OC12H8) indicates that such a carboboration pathway also provides access to related boron-derived radicals.