Molecular aromaticity is one of the most frequently exploited (yet controversial) concepts in chemistry. From the electronic-structure point of view, aromaticity is intrinsically linked to the effect of electron delocalization associated with the periodic boundary conditions in molecular topologies such as ring, strip, cage, sphere, etc. In the case of simple organic rings, the approximate relations between delocalization of electrons and the resulting observable properties (such as unusual thermodynamic stability, bond-length equalization, and abnormal chemical shifts) have already been established in the literature. However, the link between these properties in the conjugated poly-and macro-cycles (including nanorings of porphyrins) remains intriguing and controversial. The paracyclophanetetraene (PCT) could be regarded as an archetypal case here; this macrocyclic system has recently been found to exhibit auspicious redox properties that can be used to design novel anode materials with extraordinarily stable cycling performance for the nextgeneration sodium-ion batteries. The neutral form of PCT represents a locally aromatic structure with four benzene rings separated by four vinyl bridges, and its stability as well as the magnetic-response properties are attributed to the presence of four fixed π-sextets. A two-fold reduction of the compound leads to PCT 2-, which surprisingly remains very stable; this stability determines cycling performance under the fast-charge/fast-discharge condition. In contrast to the neutral form, PCT 2-exhibits a global diatropic ring current along the inner and outer 24-membered pathways, which has been interpreted as a manifestation of the π-aromatic stabilization associated with the 26π-electron pathway, in accordance with the famous "4n + 2" rule by Hückel. The validity of this interpretation, however, is called into question by the fact that the large [4n + 2]annulene type molecular rings with the system of π-conjugated bonds are only minimally stabilized by the π-resonance. In fact, to minimize the exchange repulsion between electron pairs in the π-cloud they often adopt low-symmetry configurations with noticeably alternated bonds (in other words, their resonance-electronic structure collapses to a single Kekulé form with well-localized olefinic π-bonds). Notably, it has recently been confirmed experimentally by Jirásek et al. that for the [4n + 2]annulenes (n > 3) the aromatic stabilization energy (ASE) approaches only 1 -3 kcal/mol, which is even below the upper limit for the π-π stabilization effect found in trans-butadiene (3.5 kcal/mol). Thus, given the analogy between PCT 2- and two borderline isomers of the annulene dianion (Figure ), it is anticipated that the ASE associated with the Hückel's pathways in PCT 2-may approach rather negligible values indicative of non-aromaticity. Furthermore, both configurations containing cyclically delocalized πelectrons are actually the transition structures that undergo the pseudo-Jahn-Teller distorsion (pJ-T) impairing their highly symmetric structures and the uniform distribution of π-charges 1a). The energetic preference of the partially localized over the fully delocalized configurations (as well as the fact that the latter feature imaginary frequencies associated with Kekulé vibrations) contradicts the very fundamental characteristic of an aromatic ring according to the IUPAC recommendation: "A cyclically conjugated molecular entity with a stability (due to delocalization) significantly greater than that of a hypothetical localized structure (e.g. Kekulé structure) is said to possess aromatic character". Therefore, the resonance stabilization of charge through the kekulean 26πpathways is clearly not effective challenging the notion that PCT 2-achieves extraordinary stability via global Hückel's aromaticity. A similar observation can be made for the tetraanion form, PCT 4-, which is also remarkably stable despite the presence of a global paratropic ring current indicative of the 28π-antiaromaticity in line with Hückel's rule. Considering all these facts, one can assert that π-electron delocalization over the 24-membered pathways in PCT is associated with rather negligible long-distance resonance stabilization regardless of the π-charge state. But this prompts the following questions: what is the real source of thermodynamic stability of PCT anions, and (2) does their resonance-electronic structure exhibit any similarity to the neutral compound? Recently, Stawski et al. reported crystallographic data of both anions that may facilitate solving the puzzle. The authors investigated the solid-state structures of PCT 2- and PCT 4-in diverse coordination environments and they found that the bond-length alternation (BLA) effects in vinyl bridges are significantly reduced in the former but enhanced in the latter, but in both cases the accumulation of negative charges is observed primarily in the πclouds of vinyl bridges. This clearly indicates that negative π-charge is not uniformly distributed across the conjugated bond system, and thus the cyclic delocalization of π-electrons along the Hückel pathways is indeed ineffective. Combining these findings, and considering that within benzenoid units the inner and the outer C-C bonds exhibit nearly identical lengths (as revealed by the crystal structures data), one can decipher the π-resonance electronic structure of these anions: there are eight and four ionic resonance forms that represent the π-delocalization in PCT 2-and PCT 4-, respectively (Figure ). The estimated values of ASE associated with the 26π-(blue) and 28π-electron pathways (red) are expected to approach c.a. +1 and -1 kcal/mol, respectively. However, combining the inner and outer pathways (green boxes, Figure ) gives rise to an alternative representation of the Clar structures with different numbers of π-sextets migrating over the benzenoid units, i.e., three and two π-sextets in PCT 2-and PCT 4-, respectively (Figure ). In contrast to the representation of the Kekulé structures, a rough estimation of ASE for the Clar representation (excluding the extra stabilization associated with the π-sextet migration effect) yields considerably larger values that may explain remarkable stability of the neutral PCT and its ability to remain stable upon reduction (Figure ). In particular, the effective reduction of one π-sextet in PCT 2-makes the ASE decrease formally by only a quarter, but additional π-resonance stabilization may arise from the π-sextet migration. In turn, the effective reduction of two π-sextets in PCT 4-still provides a level of π-resonance stabilization comparable to that in naphthalene (c.a. 60 kcal/mol). In this case, however, the migration of π-sextets is limited to two benzenoid units thus leaving two double (olefinic) bonds mostly localized, which agrees with the crystallographic structures provided by Stawski et al. To provide additional support for the representation of Clar structures, we used the harmonic oscillator model of aromaticity (HOMA); this index assumes values formally in the range from -∞ (potentially antiaromatic) through 0 (nonaromatic) up to 1 (ideally aromatic). HOMA values for the benzenoid units show a consistent linear decrease of the benzene-aromatic character as the number of π-sextets diminishes, moving from PCT (HOMA= 0.92) through PCT 2-(HOMA= 0.67) to PCT 4-(HOMA= 0.41). Despite reduction by half of the local aromaticity in the neutral PCT upon transitioning to PCT 4-, the benzenoid units still exhibit much more effective π-electron delocalization compared to the macrocyclic 26π/28π-conjugated pathways (HOMA= 0.64 in PCT 2-and HOMA= 0.28 in PCT 4-). This clearly indicates that the resonance of two πsextets between two benzene units in PCT 4-functions as a mechanism for the system to avoid an antiaromatic configuration. Additionally, we used the state-of-the-art π-bond delocalization function (BDF π ) to visually illustrate the potentially aromatic (BDF π > 0) and olefinic (BDF π < 0) layers of the one-electron π-density. This function unequivocally confirms our hypothesis: (1) upon reduction, the locally aromatic PCT becomes globally aromatic PCT 2- due to presence of multiple energetically equivalent Clar structures, and (2) subsequently loses its global aromaticity to adopt a semi-locally aromatic structure in PCT 4-as the number of resonance structures is reduced. In the latter, two local π-sextet migrations are separated by two olefinic π-bonds, with the almost perfect cancellation of the aromatic and olefinic layers within the BDF π picture resulting from the superposition of two Clar structures with the same number of the benzenoid and quinoidal rings (Figure ).