PPA nanobelts were synthesized using nanocopper particles as catalysts in the gas-phase polymerization of phenylacetylene. This route offers several advantages over the conventional method: copper is used instead of expensive noble metal catalysts; gas-phase reaction avoids the use of toxic organic solvents; highly crystalline PPA nanobelt arrays can be produced. PPA nanobelts were characterized by XRD, SEM, TEM, AFM, and DSC techniques. The PPA nanobelts were highly crystalline and have the cis-specific conformation. The I -V characteristics of a single nanobelt with different doped levels were characterized. All three belts show semiconductor features. An undoped PPA belt has the largest insulating gap (about 10 V). Doping the nanobelts with iodine significantly decreases the gap. The belt that underwent 30 min of iodine doping is nearly a conductor.