The polycondensation of potassium 5-cyano-4-fluoro-2-octylphenolate (1b) was carried out in the presence of 4-fluoro-4'-trifluoromethylbenzophenone (2) as an initiator for chain-growth polycondensation in a variety of solvents, and the chain-growth nature of this polymerization was found to depend on the kind of solvent. In the polycondensation of 1b with 2 in sulfolane at 150 degreesC, the. MALDI-TOF mass spectra of poly1b showed only one series of peaks due to poly1b attached with the initiator 2 unit, and the F-19 NMR spectra indicated that the ratios of the initiator unit to the end group were 1.0. Therefore, chain-growth polycondensation occured in this condition. On the other hand, the polycondensation in THF, quinoline, DMI, tetraglyme at 150 degreesC gave poly1b with broad molecular weight distributions, and the MALDI-TOF mass spectra showed two series of peaks resulting from both chain-growth and step-growth polycondensations. (C) 2004 Wiley Periodicals, Inc.