text: Maximum catalytic current density for CO reduction that can be achieved in aqueous media is only 10 mA cm based solubility of CO and diffusion limitations. The integrated maximum photocurrent under Air Mass 1.5 illumination, in the conventional Shockley-Quiesser limit for solar energy conversion for p-Si (1.12 eV), p-InP (1.3 eV), p-GaAs (1.4 eV), and p-GaP (2.3 eV) are 44.0 mA cm, 37.0 mA cm, 32.5 mA cm and 9.0 mA cm, respectively. Therefore, non-aqueous media such as DMF, acetonitrile, methanol are explored as solvent for CO electrochemical reduction. In addition, Methanol has been industrially used as a physical absorber of CO in the Rectisol method. Similarly to aqueous media system, p-Si, p-InP, p-GaAs, p-GaP and p-CdTe are explored for CO photoelectrochemical reduction. Among these, p-GaP has lowest overpotential, whereas, p-CdTe has moderate overpotential but high catalytic current density in DMF with 5% water mixture system. Main product of CO reduction in non-aqueous media is carbon monoxide. Competitive hydrogen generation is minimized in non-aqueous media. Proposed mechanism for CO reduction to CO in non-aqueous media involves single electron reduction of CO to CO radical anion and adsorption of radical anion to surface followed by disproportionate reaction between unreduced CO and CO radical anion to form CO and CO.