If the value of log BBclass is greater than 0, the compound is predicted to readily cross the BBB. Therefore, compounds with log BBclass > 0 were labeled as BBB+ and used to train the expert model, while compounds with log BBclass ≤ 0 were labeled as BBB-and used to train the anti-expert model. Similarly, compounds with QED > 0.6 were labeled as QED+ and used to train the expert model, while compounds with QED ≤ 0.6 were labeled as QED-and used to train the anti-expert model. For a detailed description of the experimental setup, refer to the the Experimental Details section in Supporting Information.