AbstractThe copolymerization of styrene with divinylbenzene in the presence of tri‐n‐butylphosphate or a mixture of di‐2‐ethylhexylphosphoric acid and chlorobenzene was studied in order to perform porous networks, solvent impregnated copolymers, etc. The diluents behave as strong precipitants allowing to prepare permanent porous copolymers having low contents of the crosslinking agent.The effects of dilution, crosslinking degree, and nature of diluent on the porosity as well as on the uptake coefficients, the specific surface area, and the average pore diameter, were studied to elucidate the manner in which such inert compounds contribute to the formation of porous networks.