It is quite remarkable that the yield is so precisely reproducible for each of the recyclable processes, emphasizing the outstanding photocatalytic reactivity. Notably, when the f-gC3N4 (Cu-free) was introduced under the same reaction conditions, the resulting yield and the regioisomeric ratio (Table , entry 16) dropped to a significant amount, thereby affirming the essential role of transition metal (Cu) in this reaction. After optimizing the reaction conditions, the kinetics of this reaction was also investigated and revealed the steady linear increase of the yield while keeping the p/m ratio of the product always constant (S2.7, ESI).