, L = tetrazole dianion) metal cluster which additionally can be described as cubic aromatic since it exhibits an electron delocalization over the entire Zn I 8 cube. The unifying feature of these molecules is that they, besides extensive electron delocalization, have a number of degenerate molecular orbital (MO) levels which are at least triply degenerate, including the highest occupied and the lowest unoccupied MOs (HOMO and LUMO). We will henceforth call these molecules truly 3D-aromatic molecules. The MO diagram of a typical 2D-aromatic molecule such as benzene and a truly 3D-aromatic molecule like B6H6 , as shown in Figure , reveals that a closed -electron shell results with 4n + 2 electrons in a 2D-aromatic molecule, while a closed shell requires 6n + 2 highly delocalized electrons in 3D-aromatic molecules with tetrahedral or octahedral structures. Monocyclic 2Daromatic molecules with lower symmetries (e.g., C2v symmetric pyridine) lack the doubly degenerate -MOs but still have -MOs that strongly resemble those of the highly symmetric archetypes (see Figure for a comparison between the -MOs of pyridine and benzene). The same applies to 3D-aromatic carboranes in relation to the highly symmetric closo-boranes (see Figure for CB5H6 -and B6H6 2-). Indeed, Schleyer and co-workers concluded that the 4-center-2-electron 3D-aromaticity of the 1,3,5,7-bisdehydroadamantane dication manifests itself in a tetrahedral orbital topology, even though the molecule does not belong to the Td point group. 3D-aromatic molecules are traditionally -conjugated. Therefore, the search for conjugated 3D-aromatic molecules and aromaticity that extends in three dimensions has recently intensified. Indeed, the term 3D-aromaticity has been used to label several different compound classes that exhibit electron delocalization in 3D. One form of aromaticity in three dimensions is the through-space (face-to-face or stacked-ring) aromaticity first observed through computations by Corminboeuf, Schleyer, and Warner in methano-bridged superphanes involving π-stacked [4n]annulenes (Figure ), and further explored both theoretically and experimentally in cyclophanes and hexaphyrin dimers. π-Capped annulenes with six interstitial electrons have also been described as 3D aromatic. However, here it should be realized that among the three aromaticity forms in Figure , it is only spherical aromaticity that fulfills the criterion of triply or higher orbital degeneracy, justifying the classification of C60 10+ as 3D-aromatic.