Next, we screened the effect of the solvent on the transformation and noticed that protic reaction mixtures boosted the reaction yield (Table , Entry 4: up to 68% in CH3CN/H2O 9:1). Fine-tuning the ratio of the reagents, the photocatalyst loading and reaction time allowed to reach an excellent 79% yield for the targeted hydroalkylation (Table , Entries 5-6). Several control experiments revealed that excluding either light, PC1 or B1 did not lead to any product formation (Table , Entries 7-8). Moreover, 3 was also not produced at elevated temperatures (Table ). Notably, the exclusion of molecular oxygen appeared to be crucial as air-equilibrated conditions led to a significantly reduced yield ( Table . a GC yields are given using biphenyl as external standard.