To examine the excited states of the HLCT emitters, theoretical calculations are conducted by exploiting the density functional theory (DFT) and time-dependent DFT (PBE0/6-31g(d,p)). The frontier orbital distributions of the ground states of the three emitters display typical HLCT characters (Supplementary Fig. spatial interactions create weak steric hindrance, resulting in a moderate dihedral angle of 36.3° between the two units. Therefore, the HLCT state of BTD-HeBr with a moderate ICT character was expected. Natural transition orbital (NTO) analyses are also performed to explore the excited states and transition characters (Fig. ). The hole of S1 was mostly distributed on the whole conjugated system, while the electron was mainly located on the BTD acceptor. In detail, the hole and electron delocalization indexes (HDI & EDI) are 4.57 and 7.91, respectively, indicating the higher the degree of delocalization of holes and the greater spread of their distribution than that of electron. Therefore, the S1 presents a hybrid feature of LE (43.8%) and CT (57.2%). To further verify the excited-state characters, the distributions of hole and electron in BTD and fluorene fragments as heat maps are shown in Fig. . In BTD, the electron composition was significantly higher at 86.2% and the hole composition was 28.8%.