into mesoporous silica SBA-15 is demonstrated. One of the novel features is the assembly of CdS nanoparticles inside the mesopores by selectively functionalizing the external surface of SBA-15 in order to avoid the possible adsorption of the cadmium ions onto this surface. (S.-M. Yang et al., September 16, Adv. Mater. 2002, 14, 1311-1314)