Correlation lengths of crystalline domains of syndiotactic polystyrene (sPS) gels prepared in different solvents, and those of derived aerogels, have been investigated by wide-angle X-ray diffraction. The correlation length (D 010), along the direction perpendicular to the ac layers of close-packed enantiomorphous s(2/1)2 helices, is strongly dependent on the chemical nature of the guest molecules not only for molecular complex phases of gels but also for the nanoporous crystalline δ phase of aerogels. Moreover, for a large series of solvents, it has been clearly established that sPS gel transparency is markedly dependent on the solvent and regularly increased as D 010 correlation length is decreased.