Three-dimensionally ordered macroporous (3DOM) syndiotactic polystyrene (sPS) and poly(p-methyl styrene) (sPPMS) are synthesized using silica colloidal crystal templates with varied diameters in the range of 548-214 nm, and the effect of polymerization space on the conformation of the resulting 3DOM polymers is investigated by spectroscopy and thermal analysis. In-situ polymerizations of styrene and p-methyl styrene within the silica templates induce the resulting 3DOM polymers with different conformations and packing of chains, which are different from those of bulk polymers prepared in the absence of templates. Polymerizations in restricted silica templates result in un-helixication of 3DOM sPS chains and helixication of 3DOM sPPMS chains.