A dihydroxo(dodecyltetraphenylporphinato)silicon (IV) and its corresponding dimethoxosilicon (IV) derivative were synthesized to examine the mesomorphic properties of the metal complexes by differential scanning calorimetry, optical microscopy, and X-ray diffraction analysis. The study of the mesomorphic behavior of the porphyrin complexes will allow a better understanding of the influence of the axial groups on the thermal behavior, which has been demonstrated for a hydroxoaluminum complex of tetraphenylporphyrin.