In order to ascertain whether preferential inclusion of toluene and biphenyl into the delta phase of syndiotactic polystyrene occurs from solution in decalin, we investigate the crystal phase formation of this polymer from solution in decalin/toluene and decalin/biphenyl mixtures of varying composition. To this end, we performed a qualitative analysis of the solid formed upon quenching the solution and drying, with Fourier-transformed infrared spectroscopy and wide-angle x-ray diffraction. In all cases, the formation of T(2)G(2) helical structures was observed. We find that the composition of the solvent mixture can have a strong effect on the X-ray spectrum of the solid, after quenching and drying. For syndiotactic polystyrene samples obtained from decalin/toluene mixtures, we find that little or no toluene inclusion occurs, unless the fraction of toluene in the solvent mixture is quite high. Conversely, biphenyl appears to be preferentially clathrated from solution in decalin, even if it is present in relatively small amounts.