We, as well as Lee and co-workers, each recently showed that the acceptor moiety is not required in MR-TADF emitter design for OLEDs. Indeed, when the nitrogen atoms in diindolocarbazoles are para disposed, there is very weak TADF as the ∆EST is moderately large, resulting in slow kRISC. Literature reported compounds DiICztBu4 and DiICzMes4 have similar ET of 2.55 (in DCM) and 2.57 eV (in toluene),