A Simplified Molecular Input Line Entry System (SMILES) provides a textual representation of a molecule, encoding its structure according to a specific grammar. In this study, SMILES notations were collected for all HBAs and HBDs to facilitate the construction of corresponding molecular graphs. For each HBA and HBD species, some atomic and covalent bond characteristics/features, as detailed in Table , were compiled using RDKit (version 2023.09.4). These atomic and bond features align with those utilized in other research works employing GNNs for the prediction of molecular and mixture properties . A graph G = (V, E) consists of a set of nodes V and a set of edges E. Each node and edge in the graph is attributed with a bit vector obtained by the one-hot encoding of the atomic and bond features according to the dimensions indicated in Table . The initial attributes of a node are represented by a vector v ∈ {0, 1} 23 , and similarly for the attributes of an edge with the vector e ∈ {0, 1} 6 . Each node in the graph represents a non-hydrogen atom, and each edge represents a covalent bond. Nodes and edges are attributed using the atomic and bond features, respectively, computed by RDKit.