Neutron diffraction experiments were carried out in order to confirm that syndiotactic polystyrene (sPS) forms crystalline complexes with 15-crown-5 (15C5) and 18-crown-6 (18C6). A strong 010 reflection was observed in both sPS/15C5 and sPS/18C6 systems, which indicates a crystalline structure where crown ether molecules are sandwiched by polymer sheets consisting of sPS helices. It was also confirmed by IR spectroscopy that the orientation of host sPS lattice was preserved during the complexation using guest-exchange phenomenon.