Free-base triphyrin[2.2.2] which features three bonders and three sites corresponds to the 𝒮 3 ℬ 3 class. Inspection of Table , Table , and Table indicate that there are 10 families, 23 genera, and 343 species. This includes species where all three bonders are attached to a single site atom (N-atom). Based on valence and steric arguments, we exclude such species from the analysis.