This new workshop is designed to complement the existing workshop, "Accelerating Reaction Discovery." It will focus on the development and applications of techniques, tools, and methods for improving the efficiency of chemical synthesis. Special emphasis will be place on catalysis of new and existing transformations, especially using sustainable and earth-abundant materials, and on the synthetic utility of emerging technologies such as flow chemistry, microwave heating, and automated synthesis. Reaction optimization through rigorous mechanistic investigations will play a prominent role in the discussion, as a thorough understanding of mechanism is central to process optimization. This workshop will foster collaborations between diverse researchers around the common goal of improving efficiency, sustainability, and cost-benefit analysis for current and future reactions and processes.