The direct hydrofunctionalization of saturated systems represents an area where HAT-based transformations have found extensive application in synthesis. Accordingly, the e-HAT could be implemented under a universal set of conditions to achieve a wide range of classical HAT reactivities (Figure ). By simply using a slight modification of Conditions B, intramolecular HAT-Giese (67), hydroarylation (71), hydropyridination (73), retroisomerization of alkene-conjugated strained-rings (75), and deallylation as a general deprotection method (77). For the intermolecular HAT-Giese with ethyl acrylate to form a quaternary carbon (50%), a modification of Conditions B was employed wherein 2 mol% of Co(tetramethyl-ethanediyl salen) (Co(salen)-2) enabled the reaction to proceed, whereas no product was observed with Co(salen)-1. This phenomenon might be explained by the efficient formation of the carbon-centred radical instead of the cobalt-carbon bond with Co(salen)-2 due to geometrical differences in the cobalt precatalysts (see SI for mechanistic rationale). As a testament to the unique tunability of e-HAT, a challenging trans-selective alkyne semireduction was achieved using Conditions B by slightly modifying the amount of HFIP to 8 equivalents and passing through 5 F/mol of electricity. Alkyne 79 was therefore reduced to the corresponding trans-alkene in 60% isolated yield and high geometric selectivity (7:1 -E/Z). Interestingly, by performing the analogous controls with HAT chemistry using silane and the same Co(salen)-2 complex, we found that such reactivity failed to translate, once again highlighting a unique feature of the e-HAT platform. The direct, E-selective reduction of alkynes can currently only be accomplished using either harsh Birch-like conditions (Li/NH3) or by enlisting an expensive Ru-based catalysis system. A. Selectivity of alkene isomerization and reduction To further understand the e-HAT processes and support the critical steps of the proposed mechanism, cyclic voltammetry (CV), UV-vis spectroelectrochemistry, DFT computations, and kinetic analysis were employed. First, we investigated the cyclic voltammetry profiles of the Co(salen)-1 isomerization system. As shown in Figure , the CV profile of Co(Salen)-1 at 50 mV/s showed a reversible redox peak at -1.98V corresponds to the Co(II/I) redox couple (step A). The addition of HFIP to the Co(Salen)-1 solution results in the observation of catalytic current. This is expected to arise from an ECECcat process corresponding to the generation of H2. Such an observation is suggestive of in-situ protonation of the low-valent Co(I) to generate the Co(III)-H (step B). The addition of both HFIP and alkene to the Co(salen)-1 solution (Conditions B) results in a slight dampening of the catalytic current. This could indicate that the alkene is reacting with the Co-H species to catalyze the isomerization reaction, diverting the catalyst from the H2 generation cycle (step C). To further support the proposed mechanism of the Co(salen)-1 system, we sought to observe the respective catalyst resting states with in-situ UV-vis spectroelectrochemistry (Figure ). Accordingly, we examined the spectroelectrochemical properties of the Co(salen)-1 under the olefin isomerization reaction mixture. Application of a stepwise reducing potential to a Co(II)-salen solution found modest decreases in absorbance for the electronic transitions at 416 nm and 492 nm, which could have resulted from either the direct reduction of the metal center to a Co(I)-salen (Step A) or redox non-innocence of the salen backbone (Figure -2, and see SI). Reduction of Co(salen)-1 at -2.03 V in presence of HFIP led to the complete disappearance of the Co(II)-salen electronic spectral features and appearance of a single UV-vis absorbance at 375 nm. Based on our previous observations, upon application of reducing potentials, we speculate that this new spectral feature at 375 nm could arise from the presence of a Co-hydride catalyst resting state (Step B), a commonly invoked intermediate within the field of Co-promoted HER catalysis. Intriguingly, spectroelectrochemical studies of the Co(salen)-1 in the presence HFIP and alkene lead to the same absorbance feature at 375 nm during active electrocatalysis. Presumably this putative Co-hydride could be competent for both Co-promoted HER as well as Co-catalyzed olefin isomerization, thus appearing in both spectroelectrochemical experiments as a plausible catalyst resting state.