To investigate the CoBr2/4,4'-dimethoxybipyridine isomerization system (Conditions A), the ligation state of the active cobalt catalyst was first identified (Figure ). A 1:1 mixture of CoBr2 and 4,4'dimethoxybipyridine resulted in a CV profile with two distinct reduction peaks for Co(II) to Co(I) (Figure ). These peaks were preliminarily assigned as the bisligated L2CoBr2 (which overlaps with CoBr2) for the less negative reduction peak and the monoligated L1CoBr2 for the more negative reduction peak. This assignment is consistent with previous studies showing that the reduction potential of bisligated cobalt complexes is in general, less negative than its corresponding monoligated species. Next, CV studies were performed with adding concentration of 4,4'-dimethoxybipyridine. At 1:1.5 Co/ligand ratio, both reduction peaks increased. The addition of more ligand caused the peak assigned as monoligated complex to decrease. Due to the overlapping peak on the reduction wave associated with the bisligated system, the oxidation wave was examined (since the reduction of unligated CoBr2 is irreversible, see SI) , wherein an increased oxidation peak was observed upon increasing ligand concentration beyond 1.5 equiv. These studies provide evidence for the preliminary assignment outlined above. Next, the effect of the proton source and the alkene substrate on the CV behavior of the Cobalt catalyst was studied. Using a 1:2 mM ratio of CoBr2/ligand where both the mono and bisligated species were present, the effect of adding 1 mM Et3NHBF4 was investigated (Figure ). A significant increase in peak current was observed for the monoligated cobalt complex, and a negligible change was observed for the bisligated species. These denote that the monoligated cobalt complex is active towards reaction with Et3NHBF4 to generate Co-hydride intermediate (Figure , step B). The addition of monosubstituted alkene to this solution resulted in a catalytic current indicative of a chemical reaction with alkene that regenerates the active cobalt catalyst. We therefore propose this as a series of chemical steps for the isomerization of alkenes (Figure , steps C to E). DFT computational analysis provided additional evidence for the proposed mechanism of olefin isomerization. Based on the divergent reactivity of the two complexes throughout the synthetic studies, it stands to reason that the salen derived catalysts operate with a different general mechanism than that of the bipyridine system. To explore this, the bond dissociation energies of various possible intermediates in such isomerization processes were calculated for both systems. According to the previous analysis, the reaction is initiated via Co-H generation, followed by its insertion into the olefin. The alkyl-cobalt intermediates of salen ligands contain weak Co-C bonds (27 kcal/mol for secondary carbon, 20 kcal/mol for tertiary carbon, Figure ) that resemble diradicals. Accordingly, we propose that steps C and E (Figure ) proceed via H-atom transfer with Co(salen)-1 system. Similarly, Figure shows that the strength of the Co-H bond in the Co(salen)-hydride complex indeed matches the C-H bonds of the substrate, which further support the thermodynamic favorability of the HAT pathway. In the case of the Co-bipyridine system (Conditions A), the strong Co-C bonds of the putative intermediates (Figure ) are perhaps more consistent with an organometallic process of inner-sphere migratory insertion and βhydride elimination. Consistent with this conclusion, the bipyridine Co-hydride species potentially involved in an HAT version of step C contain Co-H bonds much stronger than the substrates C-H bonds (Co I and Co II , Figure ) while those potentially involved in step E contain Co-H bonds much weaker than the substrate's C-H bonds (Co III , Figure ). Both assertions point to a thermodynamically unfavorable HAT pathway in the presence of bipyridine ligands.