Mesoporous silica/polymer sulfonate composite materials were prepared by simply mixing hexadecyltrimethylammonium bromide, polymer sulfonates and TEOS (tetraethoxysilane) in alkaline aqueous solution. Nation and poly(sodium 4-styrenesulfonate) were employed as polymer sulfonates. XRD patterns and nitrogen adsorption-desorption isotherms showed that the precipitates obtained had mesostructure similar to MCM-41. Especially, the crystallinity of hexagonal structure of composite materials synthesized with Nafion was high. From all the results obtained here, it is concluded that the polymer sulfonate resins might be incorporated in the wall framework of mesoporous silica matrix. However, when the excess amount of Nation was mixed, the acid sites of Nafion were significantly lost in the obtained materials. These composite materials present new classes of organically modified mesoporous silicas, where organic polymers are incorporated in the framework of mesoporous silica. They were used as catalysts for a-methylstyrene dimerization and Friedel-Crafts alkylation reaction of aromatics. (c) 2006 Elsevier B.V. All rights reserved.