Figure shows the matching of CG and atomistic SASA, indicating an excellent agreement, which reflect not only the accurate fitting of bond distance but also the choices of bead sizes. The overall comparison between COSMO-RS and Martini 3 CG partitioning free energies showed a reasonable agreement with a R² = 0.80 and MAE = 6.4 kJ/mol (Figure ). The matching between the approaches was worse for larger, branched hydrophobic fragments, such as some of the linker fragments containing several carbons and one hydrophilic group such as an ester or ether. These discrepancies are expected as experimentally it is impossible to accurately estimate these values, with any predictions becoming less trustworthy . Additionally, as already mentioned, there is an inherent error of the COSMO-RS estimates. Therefore, the main focus for selecting the types of beads was to maintain consistency between fragments, chemical groups, and other Martini 3 lipid models. Hence, the difference in partitioning free energy between the CG models and predicted values, is not an issue for the final IL models. The behavior of the ILs was later compared with atomistic models to further validate the choices.