Guest-induced crystallization of amorphous unoriented syndiotactic polystyrene (s-PS) films can generate oriented clathrate phases with the chain axis of s(2/1)2 helicies nearly perpendicular to the film plane. This perpendicular crystalline phase orientation can be maintained after lower temperature annealing procedures leading to the gamma form, where the same helical conformation is present, as well as after higher temperatures annealing procedures leading to alpha and beta crystalline forms (where trans-planar rather than helical chains are present). A high degree of orientation can be also maintained after extraction procedures leading to helical nanoporous delta crystalline form. Also guest diffusion procedures producing guest replacements into clathrate phases of s-PS films can leave substantially unaltered their possible orientation. To our knowledge, the achievement of crystalline phase orientation by simple solvent diffusion crystallization into amorphous unoriented thick films is unprecedented.