The synthesis of various tetrakis(trihalophenolato)cerium(IV) complexes from an aqueous solution and their characterisations by means of FTIR, DSC, elemental analyses, mass spectroscopy and magnetic susceptibility measurements is described. The thermal polymerisation of these complexes were carried out in the solid state and in the melt. Structural analyses of polymers were performed by H-1 NMR, C-13 NMR and FTIR spectroscopic analyses, T-g by differential scanning calorimetry, as well as the molecular weights by viscometric method. All polymers had branched structure with high T-g and low intrinsic viscosity values. (C) 2002 Elsevier Science B.V. All rights reserved.