We then examined the novelty of the generated molecules and their corresponding scaffolds. The total number of novel molecules with respect to the training and transfer learning set was reduced by 60% at the end of the transfer learning process, whereas the number of novel scaffolds only decreased marginally (Table , Supporting Information). Compared to the Enamine compound set (700M drug-like compounds) as an example of a screening compound collection, almost all generated molecules (>99%) were new, and the proportion of new scaffolds among the generated molecules increased from 75% to over 95% during transfer learning (Table , Supporting Information).