Compared with the original template molecule, the generated molecules successfully retained a similar molecular size and contour, avoiding excessive divergence in the chemical space. At the same time, the generation model created a large number of novel and reasonable structures, such as new heteroatoms, peri-condensed fused-ring structures (i.e., an atom is shared by three rings simultaneously), and new fragment connection patterns. The generated molecules still retain a large conjugated system, which is the structural basis for the optoelectronic function of the molecule, providing a structural guarantee for subsequent screening. We take the terminal group of Y6 as an example to demonstrate the partial generation ability of O 2 -GEN and examine the obtained 521 molecules. The newly generated terminal groups exhibited rich and novel structures as shown in Figure .b1. Compared with the template molecule, the number and type of rings, the types of substituents, and heteroatoms also showed greater richness. Furthermore, we selected 6 atoms on half of the ring (Figure .b2) to further test the local generation mode for fused-ring fragments. Under this condition, the chemical space explored was further compressed. Nevertheless, O 2 -GEN still presented numerous novel and valuable structures in 150 generated samples.