Just as the Materials Project has evolved from its initial release in 2011 to today, increasing in scale, scope, and structure, MPcules will continue to develop over time. We have already mentioned types of molecules that we intend to add to MPcules (e.g. transition-metal complexes and triplets). Here, we outline further plans to expand MPcules. We note that while we aim to internally develop the MPcules code(s) and dataset, we welcome usersubmitted contributions of data as well as features (in the form of code contributions to emmet-core, emmet-builders, emmet-api, and the other Materials Project packages). Calculation Methods and Sources