The aromaticity of the rings of thiophene, pyrrole, furan, and benzene annelated cyclooctatetraene (COT) derivatives and of their double charged ions was studied using the graph-theoretical theory of aromaticity. On the basis of topological resonance energy, it was found that the global aromaticity is dependent upon on the arrangement of heteroatoms in the given molecule. Relative stability of these molecules when in different charged states can been explained in terms of the topological charge stabilization rule. We expect that fusing the COT ring with an increasing number of aromatic rings will lead to an increase in the aromaticity of the molecule. According to the bond resonance energy (BRE) and circuit resonance energy (CRE) indices, local antiaromaticity of the COT ring is weakened as the number of fused rings increases, and these changes play a significant role in the global aromaticity of the molecule. For some compounds, our BRE and CRE indices do not predict the same order of magnitude of the local aromatic character of certain rings that the nucleus independent chemical shift (NICS(0) and (NICS(1)) methods predict. Finally, for the available compounds, correlations between the diatropic and paratropic chemical shifts of the protons and our ring current results were analyzed and good agreement was found.

The effect of benzene ring fusion on the aromaticity of cycl[3.2.2]azine was studied by calculating topological resonance energy (TRE), the percentage topological resonance energy (%TRE), and magnetic resonance energy (MRE). The bond resonance energy (BRE) and circuit resonance energy (CRE) indices were used to estimate the local aromaticity. Our BRE and CRE results show that the central nitrogen atom plays a significant role both in the global and local aromaticity of the compounds in our study, and contrary to what has been reported in the literature, none of these compounds are peripheral π‐electronic systems. In the case of benzene ring‐fused derivatives, benzene ring(s) exhibit relatively larger local aromaticity and reduce the local aromaticity of the central portion of cycl[3.2.2]azine to a level comparable to a corresponding non‐benzene fused parent system. Ring current results predict that a strong diamagnetic current flows around the whole molecular perimeter. The diatropic bond current results, as computed here, are in good agreement with the observed 1H‐NMR chemical shifts of these compounds.