The valence state and the mesomorphic behaviors of a homologous series of new cerium phthalocyanine double-decker complexes bearing thioalkyl substituents are described. Spectroscopic studies and Single crystal X-Ray crystallography data revealed that the metal center in this lanthanide double-decker complex is tetravalent making the whole molecule neutral and the two ligands structurally equivalent. As a consequence, the thermal stability of their mesophase is enhanced compared to those of other lanthanide phthalocyanine complexes. Moreover, these compounds show a strong tendency towards homeotropic alignment of their hexagonal columnar (Col(h)) mesophase on a glass substrate, which persist at room temperature (glass transition).