Using DFT calculations, Bredas et al. investigated the origins of the TSCT in a number of TADF emitters (Figure ). Two pathways for TSCT were identified: intramolecular π•••π and n•••π noncovalent interactions. The mechanism of the π•••π interaction is the one that is operational for XPT, XCT and XtBuCT. . However, in the cases of TRZ-oCz and TRZ-oBFCz, the computations indicated a very close packing between one of the nitrogen atoms of the triazine ring with the carbazole plane, which the authors asserted triggered noncovalent interactions between the lone-pair electrons of this triazine nitrogen atom and the carbazole π electrons. The n → π* interactions were identified as critical for enhancing the singlet-triplet spin-orbit coupling, and as a result, greatly facilitating the RISC process. Further examples based on an ortho-connection strategy include the incorporation of a dibenzofuran as the bridge in BCzTRZDBF, TCzTRZDBF and IDCzTRZDBF (Figure )