4.1 SW3x2. The non-alternant isomer of Bisanthene. The theoretical results for SW3x2 are summarized in Table . As we can verify in TABLE , all standard and double hybrid DFT calculations for SW3x2 clearly predict an open-shell singlet ground state. The antiferromagnetic spins are localized at the edges of the opposite heptagons. This also true for the ferromagnetic triplet state, as is shown below in Fig. . Actually, at the simple DFT level without MP2 corrections the energetical differences between open singlet and triplet states are rather small. However, the differences become much larger (by more than an order of magnitude) when MP2 corrections are included. This is also true for the corresponding HOMO-LUMO gaps, listed in Table . We suggest here that the (unambiguous) open-singlet ground state (with the opposite spins located at the edges of the opposite heptagons) is strongly related to the antiaromaticity of the heptagonal rings, as is shown in Fig. . This is clearly in full agreement with the conclusions of Zeng, Z. et al. In Fig. we can see that the antiaromaticity of heptagonal rings is reduced by one order of magnitude from the closed singlet (+55 ppm) to the ground state open singlet (+5 ppm). We can also verify that the more antiaromatic the heptagonal rings are, the higher the energy of the corresponding spin states. In addition, we can observe in Fig. that in all three spin states the pentagonal rings (in sharp contrast to heptagonal rings) are aromatic. This should be compared with the atomic charge distribution in the left part of Fig. , which shows a clear negative charge (red color) which renders the pentagonal rings with approximately one more electron raising the total number of π electrons to nearly six; thus approximately satisfying the 4n+2 Huckel's rule. On the other hand, the heptagonal rings are not positively charged (as in azulene). On the contrary, Thus, the open-shell ground state of SW3x2 in full agreement with the conclusions of Zeng et al. , is the result of its "irresistible wish to be diradical", as all anti-aromatic p-conjugated molecules. Focusing now on the structure of HOMO and LUMO orbitals in Fig. we can observe a new and novel effect. The HOMO and LUMO orbitals of the antiferromagnetic ground state show drastically different morphologies (in full contrast to the alternant 3x2 isomer): The HOMO orbitals (A and B) are fully localized at the edges, whereas the corresponding LUMOs are delocalized, distributed over the whole structure. This a completely new phenomenon, breaking the electron-hole symmetry which is valid for alternant GNRs and NGRs. Thus, we have localized electrons, but delocalized holes, which affects the region around the Fermi level and the corresponding Dirac points. Apparently, such phenomenon could have profound implications in spintronics and optoelectronics. For larger structures in k-space calculations this phenomenon could appear as distorted Dirac cones. 4.2 SW4x2. The non-alternant isomer of Peri-tetracene. Similar to the SW3x2 results are obtained for SW4x2. In Table we have compiled the energetic characteristics for this nonalternant isomer. 2) the energetical differences between the ferromagnetic, anti-ferromagnetic, and non-magnetic states are very small (ΔΕ< 0.1 eV), and so are the corresponding HOMO-LUMO gaps in Table . This is in close agreement with the theoretical results of ref. 2, obtained using the same PBE functional. However, when MP2 corrections are introduced (using B2PLYPD/6 +MP2) the energetical differences become larger by one order of magnitude (ΔΕ >1 eV), similarly to the case of SW3x2. Thus, the interchange between different spin states cannot take place as easy as was suggested by Mishra et al. Moreover, at the correlated B2PLYPD/6+MP2 level, similarly to the SW3x2 the non-magnetic (closed shell) state becomes energetically lower than the ferromagnetic (triplet) state. This seems to be a rather universal behavior for the SW non-alternant NGRs and GNRs, which (as before) is strongly related to their antiaromatic and electronic properties, in analogy to the key role of aromaticity for the alternant (closed singlet states of) NGRs/GNRs. The aromatic and electronic properties of SW4x2 are shown in Fig. .