Liquid-assisted grinding (LAG) with dimethyl sulfoxide (DMSO) can prepare a variety of palladium-bipyridine complexes much more rapidly than by ball milling the neat powders. The added liquid is non-innocent, and reacts to form Pd-DMSO species prior to formation of the final complex. Formation of a metal-DMSO intermediate leads this process to be ineffective for analogous zinc complexes. The mechanosynthesis kinetics can effectively be fitted to the Johnson-Mehl-Avrami-Yerofeev-Kolmogorov (JMAYK) and Finke-Watzky (FW) models in the case of neat and LAG reactions, but the LAG mechanosynthesis is most easily evaluated in terms of solution-like first order kinetics. The addition of a small amount of DMSO to the reaction mixture is so effective that reasonable yields may be achieved in 24 h without milling by periodically stirring the reacting powders.