Ionic liquids (ILs) are important solvents for sustainable processes and predicting activity coefficients (ACs) of solutes in ILs is needed. Recently, matrix completion methods (MCMs), transformers, graph neural networks (GNNs) have shown high accuracy ACs binary mixtures, superior to well-established models, e.g., COSMO-RS UNIFAC. GNNs particularly promising here as they learn a molecular grap...