Nanocrystalline mesoporous tin dioxide materials have been obtained through the controlled hydrolysis of bis(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin followed by a thermal treatment at 400-550 °C. These materials have been carefully characterized by elemental analysis, FTIR, TGA-MS, XRD, MET, N 2 adsorption, and thermoporometry. They are composed of a porous network of aggregated nanoparticles with a mesoporosity arising from the interparticle space. A careful tuning of both hydrolysis ratio and calcination temperature allowed the preparation of powders with Brunauer-Emmett-Teller surface areas ranging from 50 to 150 m 2 ‚g -1 , an average pore size between 45 and 100 Å, and a mean particle size ranging from 60 to 180 Å. The higher hydrolysis ratio favored the formation of mesoporous solids with high surface areas and low mean pore size diameter. The powders prepared at 550 °C might be advantageously used as semiconducting oxide materials in dye-sensitized photovoltaic devices.