Macronet isoporous PS gels, obtained by cross-linking of linear PS in solution with p-xylylenedichloride or 4,4 prime -bis-chloromethylbiphenyl, differ from conventional styrene-divinylbenzene (DVB) copolymers by high solvent-uptake capacity, high inner surface area, and the ability to increase their volume in any solvent, including hexane, methanol, and water.