Sintering is an important issue in creating crystalline metal oxides with high porosity and surface area, especially in the case of high-temperature materials such as metal aluminates. Herein we report a rationally designed synthesis of metal aluminates that diminishes the surface area loss due to sintering. Metal aluminate (e.g. MeAl2O4or MeAlO3−Me=Mg, Mn, Fe, Ni, Co, Cu, La, or Ce; or mixture thereof) supported on γ-Al2O3 with ultralarge mesopores (up to 30 nm) was synthesized through microwave-assisted peptization of boehmite nanoparticles and their self-assembly in the presence of a triblock copolymer (Pluronic P123) and metal nitrates, followed by co-condensation and thermal treatment. The resulting materials showed the surface area up to about 410 m2·g−1, porosity up to about 2.5 cm3·g−1, and very good thermal stability. The observed enhancement in their thermomechanical resistance is associated with the faster formation of the metal aluminate phases. The nanometer scale path diffusion and highly defective interface of γ-alumina facilitate the counter diffusion of MeX+ and Al3+ species and further formation of the metal aluminate phase.