A detailed mechanistic investigation was performed on the graphite-conjugated cobalt tetraphenylporphyrin (GCC-CoTPP) and non-conjugated cobalt porphyrin complex (Amide-CoTPP). In the first paper reported by Kaminsky et al., a dramatic enhancement in the rate of oxygen reduction reaction was observed through strong conjugation on GCC-CoTPP compared to the low/non-conjugated Amide-CoTPP (Figure ). Although both GCC-CoTPP and Amide-CoTPP can catalyze oxygen reduction reactions, Amide-CoTPP displayed an onset current density of 10 μA cm -2 at 0.66 V, whereas GCC-CoTPP displayed the same onset current at 0.72 V, revealing almost an order of magnitude improvement in turn over frequency. The strong electronic coupling provided by the highly conjugated pyrazine linkage enabled rapid electron transfer which significantly enhanced the rate of oxygen reduction.