Firstly, we generate condensed hetero-polycyclic aromatic molecules using 12 kinds of five or six-membered aromatic or anti-aromatic hetero-rings (Figure ) as building blocks. To cover the chemical space of condensed hetero-polycyclic aromatic molecules for organic op-13 toelectronic applications, our building blocks feature various compositions (including monoand di-substituted variants with B, N, O, S, and C=O), which are commonly reported in previous studies. Furthermore, when fusing the rings in original condensed hetero-polycyclic aromatic molecules and building blocks (Figure ), we allow carbon or hetero atoms to be shared by two or three rings. This approach ensures that part of the generated molecules exhibit multiple resonance features, which are widely used for the preparation of devices with narrow band emission, high luminescence quantum efficiency and have not been considered in previous open-source datasets. To avoid unnecessary resource consumption, we set the maximum ring number to 15, ultimately generating 2 M condensed hetero-polycyclic aromatic molecules.