The layered and hexagonal yttrium-based surfactant mesophases templated by anionic surfactant (CnH2n+1OSO3- and CnH2n+1SO3-) assemblies were synthesized by the homogeneous precipitation method using urea. The layered mesophase is formed of a layered but curving or bending microstructure and transformed into a hexagonal mesostructure with complex and attractive morphologies such as plate-, dish-, and crown-like shapes. The specific surface area of the mesostructured solid increases from 53 m(2) g(-1) for the layered form to 251-322 m(2) g(-1) for the hexagonal form, due to the formation of hexagonally arranged cylindrical micropores loosely occupied by surfactant molecules. The anion-exchange of the hexagonal mesophase with acetate species results in a mesoporous material with a specific surface area of as large as 545 m(2) g(-1).