In total, 10 reactive cores were selected as templates in this manner, respectively divided into five DA, three DC, and two RR ones (the corresponding reaction SMILES can be found in Section S1 of the Supporting Information). An initial set of 9 substituents to decorate the selected reactive cores were identified from the same subset of the BH9-extracted pericyclic reactions. Additionally, 5 extra cores were included to enable the generation of fused rings.