Mesoporous poly(styrene) (PS) containing various amounts of the cross-linker divinylbenzene was synthesized by a hard-templating routine using pressed pellets or fumed silica as templates Porous polymers with a surface area of 215 m(2) g(-1) and porosities up to similar to 35 vol % could be obtained. The impact of the cross-linker content and the processing on the porosity of the materials was investigated by nitrogen sorption and small-angle X-ray scattering. The surface area of the nascent porous PS increases and the pore size decreases with increasing amount of cross-linker. Furthermore, it was found that the porous polymers lose stir Face area at temperatures that are substantially below the glass transition temperature, T-g, of bulk polystyrene The loss in surface area at temperatures below 65 degrees C suggests that partial pore collapse also may be induced in the glassy state. Finally, the stability of the mesopores against solvent swelling was investigated A critical pore collapse was round at a cross-linker content of similar to 20 wt %. In this context, also the existence of traced porosity. i.e. a nonaccessible mesostructure or porosity, could be confirmed.