Based on the redox potentials (Table ), we envisaged that both 4CzIPN and pDTCz-DPmS could promote this transformation, particularly the latter. Unfortunately, while both could photocatalyze the reaction, they do so in poor yields of 10 and 16%, respectively, with a considerable amount of unreacted styrene detected in the reaction mixture by 1 H NMR spectroscopy. It is unclear at this point why the organic TADF photocatalysts perform so much more poorly than [Ru(bpy)3](PF6)2.