Removal of the nickel catalyst resulted in a non-zero yield (9%), suggesting the presence of a small purely photocatalytic background reaction, while controls without the photocatalyst, light, or LAG agent resulted in no formation of the target product. It is possible the LAG agent may play a dual role of stabilising transient nickel species as a ligand while also facilitating more efficient mixing of the reagents. Removal of the milling balls led to a yield reduction (45%), showing that the different rheology of this reaction mixture relative to the arylation described above necessitates an increased mechanochemical input for efficient reactivity. It was not necessary to use the pre-formed nickel co-catalyst, as use of NiCl2•DME and 4,4'-di- tert-butyl-2,2'-bipyridine (dtbbpy) resulted in a yield of 62%, indicating that the active nickel co-catalyst can be formed in situ in the absence of bulk solvent. Finally, a yield of 77±0% was obtained utilising the V2 holder and a single larger milling ball. We then cross-compared the efficiency of these optimized conditions to the solution-state reaction, Figure . At a literature reported concentration of 0.02 M, and under air, the reaction is complete within the same two-hour window as the mechanophotocatalysis reaction (82±1%). Once again, the solvent-minimized version provides a competitive yield (77±0%), with an approximately 180-fold reduction in reaction solvent use. It should be noted that the dilute solution-state reaction used in this reaction (>500 equivalents of DMA with respect to the limiting reagent) can be modified to a more concentrated version at 0.1 M for this system without significantly impacting the yield over the 2-hour window (81±2%); notably, even under these conditions the mechanophotocatalysis reaction still proceeds with an approximately 36-fold reduction in the usage and waste of the reaction solvent.