High quality poly(p-phenylene) (PPP) film with conductivity of 0.015 S cm(-1) was synthesized electro-chemically by direct anodic oxidation of p-terphenyl (PP) oligomers in boron trifluoride diethyl etherate (BFEE) containing 37.5% CH2Cl2 (v/v). The oxidation onset potential of PP in this medium was measured to be only 1.23 V vs. saturated calomel electrode (SCE), which was lower than that determined in CH2Cl2 + 0.1 mol L-1 Bu4NBF4 (1.87 V vs. SCE). As-formed PPP films showed good electrochemical behavior, good electrochromic property and good thermal stability. The structures and morphology of doped and dedoped PPP were investigated by UV-vis, FTIR, and Scanning electron micrographs. The infrared spectroscopic measurements for the estimation of chain lengths revealed that PPP was composed of about 10 phenyl rings. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2688-2694, 2010