1. Objective-oriented synthesis planning Users may have very different objectives for their synthesis tasks, including shorter synthesis routes, use of less hazardous reagents, higher yields, or greener feedstocks. These objectives are translated into heuristics (e.g., yield threshold, unfavoured solvents, preference of substructures etc.) to guide the search. This approach also allows close interaction between users and our system. A user iteratively refines their search to obtain the satisfactory set of results.