Using electric current as a traceless reagent in transition metal catalysis has opened up a new avenue for the development of sustainable transformations. Transition metal complexes can serve as electron transfer mediators to reduce overpotentials, and meanwhile bring in rich and tunable reactivities for electrosynthesis. Cobalt complexes were among the first explored metal-based redox catalysts in electrosynthesis due to their multiple accessible oxidation states. In particular, vitamin B12 and its mimics (cobaloxime, CoSalen, etc.) have received considerable attention for their good redox cyclability and distinct reactivities at Co I , Co II , and Co III oxidation states, respectively (Figure ). For example, the square planar four-coordinate Co I "supernucleophile" has been employed for electroreductive dehalogenation, Giese reaction and carboxylation since 1980s, and more recently in Co-H-catalyzed olefin isomerization and related reactions via hydrogen-atom-transfer (HAT). The combination of electrochemical HAT reaction and copper-mediated radical functionalization has resulted in an elegant solution for enantioselective hydrocyanation of conjugated alkenes. Electrochemically going beyond the common oxidation states (Co I/II/III ) may allow one to explore new reactivity space. An inspiring example is Ackermann's discovery of a formal Co IV intermediate in electrocatalytic C-H functionalization reactions. In VB12-related systems, cationic organocobalt(IV) complexes have been known since 1970s (Figure ). Their organometallic radical cation nature makes them susceptible to nucleophilic displacement at the alkyl ligand. This was recently leveraged in a series of HAT-initiated oxidative hydrofunctionalization reactions using stoichiometric chemical oxidants such as N-fluoropyridiniums, hypervalent iodine reagents and persulfates. In our previous work, a well-defined organocobalt(III) complex was electrochemically characterized, where the Co III/IV oxidation proved accessible at quite low potential (Ep/2 vs Fc + /Fc ~ -0.01 V). However, to the best of our knowledge, such a Co IV state in VB12-related catalysts has not been explored in electrosynthesis.