The reactions between metal (Pb or Bi) clusters formed by laser ablation and hexafluorobenzene (C6F6) seeded in argon carrier gas were studied by a reflectron time-of-flight mass spectrometer combined with a photoelectron spectrometer. The adiabatic electron affinities of the dominant anionic products, PbmC6F5- and BimC6F5- (m = 1-4) complexes, were obtained from the photoelectron spectra with 193 rim photons. It was found that the EAs of PbmC6F5 are higher than those of the pure Pb-m clusters and that the photoelectron spectra of BimC6F5- show sorne similarities to those of Bi-m+1(-). Theoretical calculations were carried out to elucidate their geometric structures and bonding modes. The adiabatic detachment energy and simulated spectrum based on Koopmans' theorem for the optimized structures of each complex were in agreement with the photoelectron spectroscopy results. The most likely structures for each species were obtained. The analysis of the molecular orbital composition provides evidence that the C6F5 group contributes a single electron to bind with metal Clusters through the M-C sigma bond.