The robust immobilization and activity regulation of molecular catalysts on solid electrodes have remained persistent challenges in catalysis. Herein, cucurbituril (CB[7]) acts is first demonstrated as a bifunctional medium to firmly immobilize molecular catalyst CoTMPyP onto various metal oxide electrodes, including TiO2, BiVO4, α‐Fe2O3, and WO3, through host‐guest and electrostatic interactions. This approach not only secures stable attachment of the catalyst but also optimizes its electronic structure and catalytic activity. The CB[7]‐mediated supramolecular electrodes exhibit exceptional performance in electrocatalytic oxygen evolution reaction (OER), ethanol oxidation reaction, hydrazine oxidation reaction, and photoelectrocatalytic water oxidation. For instance, TiO2‐CB[7]‐CoTMPyP electrode achieves a turnover frequency (TOF) of 5.30 s−1 at an overpotential of 600 mV for OER, and BiVO4‐CB[7]‐CoTMPyP photoanode delivers a water oxidation photocurrent density of 6.00 mA cm−2 at 1.23 V versus RHE under simulated solar irradiation. Mechanistic studies reveal CB[7] plays a critical role beyond merely serving as a linker: it enhances charge accumulation around the cobalt sites, promotes reactants adsorption at these sites, reduces reaction energy barrier, and accelerates charge transfer rate, thereby significantly boosting catalytic activity. This work provides a groundbreaking pathway for the design and fabrication of cost‐effective, high‐performance molecular‐based electrodes for (photo)electrocatalytic reactions.
