We also contend that photosubstitution of 4CzIPN under the reaction conditions may additionally play a role in the yields obtained. Indeed, Yields for the pinacol reaction refer to combined yield of the meso:dl isomers. Reaction conditions followed are those shown in Figure unless otherwise noted (refer to SI for further details). b Reaction run for 24 h. c Value taken from reference 28 using MeCN as the solvent, 2 equiv. NBu3 (in replacement of DIPEA) and 450 nm irradiation for 15 h.