On the aromaticity of fully -conjugated cage macrocycles: Despite the obvious three-dimensional structures of 1 and 1 6+ , and that the globally aromatic characters of the D3 symmetric molecular cages may seem apparent, they are not 3D-aromatic and do not follow the 6n + 2 rule. Instead their aromaticity can be understood in terms of the conventional Hückelaromaticity of polycyclic aromatic hydrocarbons, which in most cases is two-dimensional. We therefore label these compounds as 2D-aromatic-in-3D. Also 1 and 1 6+ can be viewed as expanded naphthalenes (Figure ) where the middle tether has been elongated so that the -electron counts in the three macrocyclic paths become equal. To check the aromatic character of these macrocycles, we use an electronic index, i.e. EDDB, over other descriptors, considering that electron delocalization is a necessary condition for 3D-aromatics.