A procedure of the template displacement by organosilanes was utilized to prepare pure-silica and cerium-substituted mesoporous materials with tailored surface functionality. These two self-assembled mesostructured systems exhibit hexagonal arrangement of mesopores but they show different reactivity with respect to organosilanes. Several samples with different pore size and functionality were prepared and for the first time a cerium-substituted mesostructured silicate was functionalized. Some peculiarities of organosilane interactions with the self-assembled cerium-substituted silicates reflect the difference in the acidic and coordination properties of cerium centers in the mesostructure. The study of the template displacement kinetics shows that about 4 h are needed to remove 70% of surfactant and about twice longer time is required for its complete removal. In addition, it is shown that the template displacement procedure stabilizes the ordered mesoporous structures.