The syntheses of distorted tetrahedral bis(pyridine)bis(trihalophenolato)cobalt(II) complexes from an aqueus solution were achieved and their characterization by FT-IR, X-ray, DSC, UV-visible and elemental analysis in solid state or in melt form is reported. Polymerizations of these complexes were accomplished either at constant temperature, employing different time intervals or constant decomposition times while varying the temperature range. The slow decomposition at constant temperature leads to long chain products, whereas long chains formed at higher temperatures were during a constant time. The resulting poly(dihalophenylene oxide)s were characterized by FT-IR, H-1 NMR, C-13 NMR spectral analysis, differential scanning calorimetry and molecular weight determinations by viscometric method. (C) 2001 Society of Chemical Industry.