From a thermodynamic analysis, we expected pDTCz-DPmS to perform well in this reaction, particularly in the reduction of the N-(acyloxy)phthalimide (since Ered = -1.65 V vs SCE in THF for pDTCz-DPmS). Herein, we report how divergent mechanisms for the same reaction are accessible and how this complicates the comparison of performance of different PCs.