In this project we propose to develop new methodologies to prepare and screen large libraries of homogeneous catalysts based on supramolecular (self-assembled) ligands using droplet-based microfluidics. Presently, the discovery and design of efficient homogeneous catalysts still relies on time intensive trial-and-error methodology. To overcome these limitations, a new paradigm shift for the discovery of effective ligands relies on the supramolecular self-assembly of libraries of ligand through reversible non-covalent interactions. This significantly increases the potential chemical space within which an optimal ligand set can be found. The full potential of this methodology is impeded by current synthesis and screening techniques which rely on macroscale (mL) trial for all the ligands sets and reaction conditions. One effective strategy to increase the rate at which reactions can be performed at is through extensive miniaturization of the reaction vessel. Recent advances in droplet-based microfluidics have enabled the effective screening of reaction conditions on a nano- to pico- liter scale. We thus propose to develop, in collaboration with a lab-on-a-chip research group, a modular droplet-based microfluidic device which will enable the generation, within a nanoliter droplet, of supramolecular catalyst made up of self-assembled ligands around a transition metal. These catalytic droplets will then be merged with a stream of reactants to form a nanoliter-size reaction size vessel which will enable the catalytic activity of the self-assembled catalyst to be evaluated. The intended outcome of this project is to greatly accelerate the speed at which an active catalyst can be identified at. This will have a broad impact on the chemical community for which screening methodologies have become an integral part of the discovery process (e.g. drug discovery).