to an E*ox of -1.53 V (c.f. E*ox = -1.7 V vs SCE for fac-Ir(ppy)3), which is more photoreducing than all but one of the organic PCs shown in Figure . Additionally, it is commercially available at a significantly lower price than 4CzIPN (£147.00 for 200 mg compared to £864.00 per 250 mg for 4CzIPN). Due to the near orthogonal conformation adopted by the donor, the oscillator strength for the lowest energy charge-transfer (CT) transition is exceedingly low, which translates into a low-intensity low-energy absorption band (λabs = 381 nm, ε = 2000 M -1 cm -1 in DMF).