The study demonstrates that a nitrile-modified Metal-Organic Framework (MOF) can act as a CO₂ solvation layer, increasing its local concentration by ~27-fold compared to bulk electrolyte. This MOF, when assembled over a Bi catalyst in a Gas Diffusion Electrode (GDE) setup, significantly enhances the CO₂-to-HCOOH conversion, achieving over 90% selectivity and partial HCOOH currents of 166 mA/cm² at ~0.9 V vs RHE. The MOF improves catalysis by stabilizing reaction intermediates, as confirmed by operando infrared spectroscopy and Density Functional Theory (DFT) simulations. This approach provides a new molecular strategy to enhance heterogeneous electrochemical CO₂ reduction, bringing it closer to practical implementation.The study demonstrates that a nitrile-modified Metal-Organic Framework (MOF) can act as a CO₂ solvation layer, increasing its local concentration by ~27-fold compared to bulk electrolyte. This MOF, when assembled over a Bi catalyst in a Gas Diffusion Electrode (GDE) setup, significantly enhances the CO₂-to-HCOOH conversion, achieving over 90% selectivity and partial HCOOH currents of 166 mA/cm² at ~0.9 V vs RHE. The MOF improves catalysis by stabilizing reaction intermediates, as confirmed by operando infrared spectroscopy and Density Functional Theory (DFT) simulations. This approach provides a new molecular strategy to enhance heterogeneous electrochemical CO₂ reduction, bringing it closer to practical implementation.