The synthesis of "side chain" functionalized MCM-41 inorganic-organic hybrids, through the exchange method of the template with the cationic organosiloxanes (CH3O)(3)SiCH2CH2CH2NH3+Cl-, (CH3O)(3)SiCH2CH2CH2NHCH2CH2NH3+Cl-, and (CH3CH2O)(3)SiCH2CH2CH2N(CH3)(3)Cl-+(-) is reported. The first two derivatives are converted to free basis by neutralization of the acidic forms with Na2CO3. After the exchange and neutralization reactions, the as received derivatives retain the hexagonal symmetry of the original MCM-41 material, whereas, due to the high loading of the pore channels of the MCM-41 silica with the organo-modifier, the final solids exhibit rather small BET surface areas (similar to100 m(2) g(-1)) and microporosity. The functionalized organic moieties, covalently attached to the walls of the MCM-41 mesoporous silica, exhibit the characteristic reactions of the particular end groups, including nucleophilic substitution reactions, chelation of transition metal ions, and anion exchange behavior.