The mesomorphic phase transition behavior of a series of long-chain metallotetraphenylporphyrin complexes (C12TPPM, M: Co, Ni, Cu, Zn, Pd, Pt, V=O, AI(OH), Mo=O(OH) and Si(OH)2) were compared to reveal that the intermolecular interaction by the axial group significantly affects the columnar arrangement. Furthermore, it was indicated that the more rigid columnar backbone with a capability of free rotation of disc-shaped molecules leads to the formation of hexagonal and tetragonal arrays of columns. © 2001 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint, a member of the Taylor & Francis Group.