Abstracto,m,p‐Polyphenylenes were prepared by oxidation‐cationic polymerization of biphenyl and then pyrolyzed up to 800°C. The o,m,p‐polyphenylenes as well as their pyrolysis residues were doped with anhydrous FeCl3from their solution in acetonitrile. The real part of the alternating electrical conductivity σ′ of the undoped and doped materials was determined at room temperature.Decreasing σ′‐values of pyrolyzed residues at 600°C without doping were observed because of the large weight losses during the pyrolysis leading to chain scission reactions within the polymer. At higher pyrolysis temperatures (i.e. 700°C, 800°C) the σ′‐values are increased due to the formation of closed aromatic systems in the polymer. The doped materials have higher σ′‐values in relation to the corresponding specimens without doping, with the exception of the pyrolysis residues at 800°C. The dependence of doping effect and time was also determined. The transition of the organic polymer to the pyropolymers can be followed and characterized by the measurement of alterna