The SMILES representations of Markush structures were downloaded from the SwinOCSR 24 repository and the images were generated using the CDK depiction generator with a resolution of 299 x 299 pixels. Character-based tokenisation was applied in both cases. Both models were trained on a set of 1 million structure depictions and tested on a set of 102,400 molecules from the whole dataset (selected using the MaxMin 50 algorithm) which were depicted as separate images; these molecules were not included in the training data.