The ESR of PPy films doped with Co(W~2O~7)~6^1^0^- and CuW~1~2O~4~0^6^- ions were reported and discussed. Results show that heteropolyanions not only play the role of neutralizing electricity in the PPy film, but also interact with the PPy molecular chain to form some adducts. The adducts affect the electronic structure of the PPy film and are unstable at more positive or more negative potentials. Dysonian ESR lineshape was recorded for the dry PPy film with CuW~1~2O~4~0^6^- for the first time.

Key words: HETEROPOLYACID, MEMBRANE ELECTRODES, DOPE, ELECTRON SPIN RESONANCE, ADDITION COMPOUNDS, POLYPYRROLE, CONDUCTING POLYMER, POLYANION