While we have tried to retain a large amount of flexibility when it comes to what chemistry can be described, i.e. which atom types and valences are allowed, there is still examples of chemistry that we are currently incapable of describing properly. This includes the examples highlighted in the manuscript such as boron hydride clusters and the perchlorate ion. Future work will include expanding the chemistry that can be described while retaining and improving the robustness and reliability of the Hückel method. One possible improvement is to take into account the preferred oxidation states of the TMs. Especially in cases where multiple ligand charges result in chemically reasonable structures, one could let the TM decide which to choose based on a prioritized list of oxidation states. Other improvements would involve proper logging of potential issues like unusual TM oxidation states or uncommon ligand charges or coordination environments. We expect that how the community will use this tool will guide the direction of improvement, when undoubtedly problematic cases that we have not thought of arise. The comparison in Table was done between CSD SMILES and DFT based SMILES. We perform the same comparison between the CSD SMILES and the CSD based Hückel SMILES and show the results in Table . It is clear that using the CSD structures directly yields a higher similarity. This is mainly attributed to the fact that we avoid potential coordination issues as bonds could be broken or formed during DFT optimization. For the Resonance TMC comparison there is an increase of ≈ 6000 equal SMILES when using the CSD structures.