Electrochemical processes are vital for global decarbonization efforts because they are central to many energy-efficient storage and conversion technologies and can also be leveraged for large scale chemical manufacturing. In the context of these energy applications, it is necessary to understand factors that control the kinetics and selectivity of electrochemical reactions. At the electrode level, many factors, including the chemical composition, atomic or molecular structure, surface area, and morphology, have been leveraged to direct electrochemical reactions. An emerging strategy is to geometrically confine the electrochemical reaction within a porous electrode material. This places a physical boundary around the electrochemical reaction and thus defines the reaction microenvironment, while also spatially restricting the reactants and products. Experimental studies of nanoconfinement effects on electrochemical reactions require electrochemical interfaces with well-defined environments. In this presentation, I will discuss our materials chemistry approach to define the confined electrochemical environment within molecularly pillared transition metal oxides, and our study of electrochemical reactions taking place within these electrodes using in situ and operando electrochemical methods.