Datasets. We use benchmark datasets for molecular optimization, which aims to generate ligand molecules for inhibition of two proteins: glycogen synthase kinase-3 beta (GSK3β) and c-Jun Nterminal kinase 3 (JNK3). The dataset, originally extracted from ExCAPE-DB , contains 2665 and 740 actives for GSK3β and JNK3 respecitvely. Each target also contains 50,000 negative ligand molecules. Following previous work , we adopt the same strategy of using a random forest trained on these datasets as the oracle property predictor.