Proton exchange membrane (PEM) electrolysis is one of the waters splitting techniques available for producing green hydrogen. As such, improvement of the membrane ion conductivity will result in improvement of hydrogen production. Ionic liquids have recently been reported to enhance ionic conductivity of PEM. Herein, a screening method to select suitable ionic liquids for the development of efficient proton exchange membrane. COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) was used to predict the ionic conductivity as well as the compatibility of the ions with the Nafion� through the interpretation of �-profile as well as interaction energy of the selected cations and anions. It was found that the anions namely of trifluoromethanesulfonate and nitrate with the cation of ammonium and imidazolium may be the best candidate for the ILs to be incorporated to Nafion� for polymer electrolyte membrane (PEM) as the combination gives high ionic conductivity with considerable high interaction towards Nafion�. It is to be highlighted that the ionic liquids mainly interact with Nafion� through the anion as implied by the high interaction energy of the anion towards Nafion� compared to the cation. © 2023, Association of American Publishers. All rights reserved.