These two photocatalysts should therefore have behave similarly to 4CzIPN (Eox* = -1.04 and Ered* = 1.35 V 17 ) and thus would not be appropriate to use in reactions that require more highly photoreducing catalysts. We thus targeted identifying MR-TADF compounds that would be more stronger photoreducing and still leverage the distinct advantages of the photophysical properties endemic to this class of compounds. Figure ), which has an intense absorption band in DCM at λabs of 437 nm (ε = 24.6 × 10 3 M - 1 cm -1 ); 28 a tert-butyl-substituted derivative tDABNA that has a slightly red-shifted, intense absorption band at λabs of 445 nm 29 though the authors did not report its molar absorptivity; a carbazole analogue to DABNA-1, CzBN that has a red-shifted absorption band at λabs of 457 nm in toluene; and a tert-butyl-substituted analogue, DtBuCzB, that possesses the most redshifted absorption band of the four compounds at λabs of 467 nm in toluene. For the latter two compounds, no molar absorptivity data were reported. The four photocatalysts are each strongly photoreducing, ranging from CzBN (Eox* = -1.51 eV) to tDABNA (Eox* = -1.98 eV) (Figure ). These have comparable photoreducing strength to recognized strongly photoreducing literature photocatalysts fac-Ir(ppy)3 (Eox* = -1.73 V) and Ph-PTZ (Eox* = -2.10 V) (Figure ). reduction is irreversible at Ered of -1.77 V in DCM (the electrochemical window of THF is not sufficiently broad for the reduction to be recorded in this solvent) (Figure ). The collated electrochemical data are found in Table and S1.