Abstract The reaction between (h5-cyclopentadienyl)carbonyl(triphenylphosphine)iridium and bis(pentafluorophenyl)acetylene has been investigated in detail. As in earlier studies involving the analogous cobalt and rhodium complexes, the metallocyclic product 1-(h5-cyclopentadienyl)-1-triphenylphosphine-2,3,4,5-tetrakis-pentafluorophenyl)iridole (3) has been obtained, although in very low yield. A variety of highly fluorinated organic products have also been isolated and identified, including hexakis(pentafluorophenyl)-benzene (5), Zraws-1,2-bis(pentafluorophenyl)ethene (6) and 1,2,3,4-tetrakis(pentafluoro-phenyl)naphthalene (4). The latter product has been synthesized by an independent method. Reaction mechanisms to account for the formation of 4 under these conditions are discussed.