(ET = 2.64 eV ) and benzophenone (ET = 3.00 eV ). Beyond CDCBs, other D-A TADF PEnT PCs include pDTCz-DPmS and DI-PF (Figure ). pDTCz-DPmS (ET = 2.93 eV) possesses a suitable ET to photocatalyze the E/Z isomerization of stilbene (ET = 2.2 eV), producing 63% of the Z-isomer, while a similar yield of 66% was reported using DI-PF (ET = 2.38 eV), despite its lower triplet energy. For pDTCz-DPmS, the moderate yield may be due to its ET being higher than that of Z-stilbene (ET = 2.5 eV), thus permitting an unproductive back isomerization. 4CzIPN produces an 87% yield of Z-stilbene and hence provides the highest yield compared to the other D-A TADF PCs in this analysis. Using a substrate with a higher ET like diisopropyl fumarate (ET = 2.7 eV), results in a more efficient isomerization, with 81% formation of the diisopropyl maleate. 4CzIPN, by contrast, produced only 6% of the isopropyl fumarate ostensibly due to its too low ET of 2.68 eV. A second class of TADF compounds are so-called multi-resonant TADF (MR-TADF) emitters.