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.