For electrochemical upgrading of small molecules, most reaction pathways require multi-step electron and proton transfers. Thus, selectivity is highly dependent on the applied potential. Electron/proton delivery can be controlled via ligand design or mediators, but there are limitations to the potentials used to match electron transfer to/from the ligand/mediator with the catalyst/substrate. To circumvent this, we will study dual-input redox control using dynamic potential variation or separate electrocatalysts and photocatalysts that operate in tandem to expose active sites and intermediates to different redox powers in one environment. Mild potentials will be applied to the electrode while introducing photoredox mediators in solution, as thin films, or as intramolecular appendages, which offer significantly higher driving forces for charge transfer, and can be studied with our uHTE methods. We will create a handle for tuning electron delivery that facilitates challenging product selectivity, such as CO2 reduction to CH2O, CH4 oxidation to CH3OH, or H2S oxidation to SO42–. Increasing the inputs for charge transfer will teach important lessons on how to better match redox thermodynamics.