Silica-based nanoparticulated bimodal mesoporous materials with high Zr content (43 Ն Si/Zr Ն 4) have been synthesized by a one-pot surfactant-assisted procedure from a hydroalcoholic medium using a cationic surfactant (CTMABr = cetyltrimethylammonium bromide) as structure-directing agent, and starting from molecular atrane complexes of Zr and Si as hydrolytic inorganic precursors. This preparative technique allows optimization of the dispersion of the Zr guest species in the silica walls. The bimodal mesoporous nature of the final high surface area nano-sized materials is confirmed by XRD, TEM, and N 2 adsorption-desorption isotherms. The small intraparticle mesopore system (with pore sizes around 2-3 nm) is due to the supramolecular templating effect of the surfactant, while the large mesopores (around 12-24 nm) have their