The adsorption and immobilization of tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)(3)](2+)) in mesoporous silicas (C18-FSM) modified by the introduction of aluminum as well as sulfonic acid groups were investigated. The complex was immobilized by the cooperative effects of electrostatic interactions between [Ru(bpy)(3)](2+) cation and sulfonic acid group and the interactions with the phenyl rings of the mesopore surface and the bipyridine rings.