What deserves more attention is that the charge transition process happens on the whole 8-rings of its [8]helicene structure of BN[8]H-BO while only 6-rings for BN[8]H-ICz. This means that though the same geometrical [8]helicene structures of both emitters, different [8]helicene and [6]helicene electronic structures can be obtained for BN[8]H-BO and BN[8]H-ICz, respectively, from the viewpoint of charge density transition process during singlet radiation. The NTO analysis of S1 for both emitters also supported the above conclusion (Figure ).