The electropolymerization of benzene on a Pt electrode was investigated in a composite electrolyte of boron trifluoride diethyl etherate and trifluoroacetic acid with a volume ratio of 2:1. The oxidation potential of the monomer in this medium was measured to be about 1.5 V (vs. SCE) instead of 2.0 V found in liquid SO2 at a low temperature. The polyphenylene films synthesized by this technique are homogenous and flexible and can easily be cut into any shape such as fibres, circles and triangles. In particular, the film had a linear chain structure with a degree of polymerization of about 20 according to its FTIR spectrum.