Polynaphthalene (Pnap) was electrosynthesized through the direct oxidation of naphthalene in boron trifluoride diethyl etherate and was characterized with IR and Raman spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and thermogravimetric analysis. Raman spectra of oligonaphthalene were calculated with Gaussian 98 at the B3LYP/6-31G* level. Combining the computational and experimental results, we assigned the Raman bands of pristine Pnap. The Raman bands related to the chain-stretching vibrations of Pnap around 1600 cm(-1) shifted to higher wave numbers as the polymerization degree increased. This phenomenon was in contrast to that of other conducting polymers bearing simple aromatic rings, such as polythiophene and polyfuran. The reason was that the condensed ring of Pnap and the steric repulsion of the interring hydrogen atoms prevented the elongation of conjugation sequences with the polymer chain length. (C) 2004 Wiley Periodicals, Inc.