Furthermore, by decorating the edge of 3T-b with six and nine nitrogen atoms we obtained 3T-c and 3T-d (see Fig. ). Here, the aza nitrogens along the rim create by themselves an alternating electron donor-electron acceptor pattern and the borazine core is not actually needed to observe ST inversion. Rather, in 3T-c and 3T-d the central BN 3 unit is harmful to ST inversion, causing loss of ST inversion for 3T-c and shrinking the inverted ST gap region for 3T-d. (see Fig. ). Accordingly, in the PPP π-electron only picture, C 12 N 6 H 12 and C 9 N 9 H 9 rings in an idealized planar geometry are the most promising structures for ST inversion with ST gaps as negative as -0.24 eV and -0.7 eV, respectively. ∆CCSD(T)/pcseg-1 calculations, detailed in SI Section S5, corroborate these findings.