While both aqueous and organic solubility models have standalone utility, here we assess their applicability when combined together to find organic co-solvents, which are important in areas such as pharmaceutical molecule development and electrochemical hydrogenation of hydrophobic molecules. We consider a good co-solvent to be an organic solvent that is miscible with water and enhances the aqueous solubility of a hydrophobic organic molecule. The water/organic co-solvent mixture retains the hydrophilic, aqueous nature of the system, but the addition of an organic solvent that solubilizes the hydrophobic molecule enhances its concentration in such a system. In the case of electrochemical hydrogenation of essential oils and bio-oils, it is often desirable that the system has an aqueous nature so water can serve as an abundant proton source for the reaction. However, the low solubility of hydrophobic molecules in water limits the range of concentrations in which the reaction can be performed.