A new aluminothermic combustion synthesis route to TiB2-Al2O3 composite was found, using the reactants 2Al(2)O(3)(.)B(2)O(3) (Al4B2O9), TiO2, and Al. Microwave-driven combustion of these reactants in inert atmosphere yielded TiB2 + Al2O3 as the only products detected by X-ray diffraction analysis. The aluminoborate reactant is not moisture-sensitive or water-soluble, unlike boron-containing oxide reactants used previously.