Having identified optimal conditions for this aerobic mechanometallaphotoredox reaction, we proceeded to benchmark it against the corresponding solution-state reaction. Under both aerobic and anaerobic conditions, the solution-state reaction is complete within the same 3-hour time window used in the mechanophotocatalysis experiment (80±1 and 83±4%, respectively), Figure . The mechanophotocatalysis reaction provided a competitive yield (76±1%) whilst providing a >28-fold reduction in the consumption and waste of the reaction solvent. As the rheology of the mixture significantly impacts the mixing efficiency of the reagents, we assessed whether the use of liquid substrates in place of the solids 1a and 2a would impede the efficiency of the solvent-minimized reaction, Figure . Under the previously optimised LAG and auxiliary loading conditions, the reactions preceded in high yields regardless of the physical state of the starting materials: the reaction of 2a with the liquid 4-bromobenzotrifluoride (1b) afforded the arylated amine product in 78% yield, while the reaction using the liquids 1b with piperidine (2b) benefitted from a lower catalyst loading to deliver 82% yield of the coupled product.