Figure illustrates the progress made within the OpenFF family of force fields with respect to GAFF-2.11 in the benchmark of dataset (ii). Smirnoff99Frosst and GAFF-2.11 almost overlap, performing worse than all other investigated force fields. Improvements can be noticed in OpenFF-1.3.0 and more so in the most recent release OpenFF-2.0.0, which clearly performs better than its predecessors. Indeed, OpenFF-2.0.0 predicts 44.4 ± 0.4% of conformers within 1 kcal/mol of QM, OpenFF-1.3.0 42.2 ± 0.4%, GAFF-2.11 41.2 ± 0.4% and Smirnoff99Frosst 40.0 ± 0.4%