Pacman dinuclear Co triphenylporphyrin-tri(pentafluorophenyl)porphyrin and dinuclear Co bis-tri(pentafluorophenyl)porphyrin , anchored at the two -positions of a benzene linker, are synthesized and examined as electrocatalysts for the oxygen reduction reaction (ORR). Both dinuclear Co bisporphyrins are more efficient and selective than corresponding mononuclear Co tetra(pentafluorophenyl)porphyrin and Co tetraphenylporphyrin for the four-electron electrocatalytic reduction of O to water. Significantly, although the ORR selectivities of the two dinuclear Co bisporphyrins are similar to each other, outperforms , in terms of larger catalytic ORR currents and lower overpotentials. Electrochemical studies showed different redox behaviors of the two Co sites of : the Co/Co reduction of the Co-TPP (TPP = triphenylporphyrin) site is well-behind that of the Co-TPFP (TPFP = tri(pentafluorophenyl)porphyrin) site by 440 mV. This difference indicated their different roles in the ORR: Co-TPFP is likely the O binding and reduction site, while Co-TPP, which is generated by the oxidation of Co-TPP on electrodes, may function as a Lewis acid to assist the O binding and activation. The positively charged Co-TPP will have through-space charge interactions with the negatively charged O-adduct unit, which will reduce the activation energy barrier for the ORR. This effect of Co-TPP closely resembles that of the Cu site of metalloenzyme cytochrome oxidase (CO), which catalyzes the biological reduction of O. This work represents a rare example of asymmetrical dinuclear metal catalysts, which can catalyze the 4e reduction of O with high selectivity and significantly improved activity.