The PPP parameters for carbon atoms date back the 1950s, 53 are well-defined and transferable across different molecules. For carbons, we set the on-site energy to zero, use a standard on-site electron-electron interaction value of U C = 11.26 eV, and a nearestneighbor C-C hopping value of t = -2.4 eV. For pyrrole nitrogen atoms, there is no single set of PPP parameters that is universally accepted. Accordingly, we used the PPP parameters we identified for the nitrogen-centered 2T triangulenes in Ref. 11, setting the on-site electron-electron repulsion at U N = 15 eV and the site energy ε py N at -13 eV. Similarly, multiple sets of PPP parameters exist for boron atoms. We fixed the boron on-site Coulombic repulsion at U B = 10 eV and fine-tuned the boron site-energy ε B to best match the experimental spectra of 3T-a. The hopping integrals for B-N, B-C, and C-N bonds were set equal to that for C-C bonds, a choice that has a minimal impact on the results (see SI Section S3). For the molecular geometry, we set all angles to 120°and all bond lengths to 1.4 Å. Results for different geometries are marginally different, as detailed in the SI Section S3.