The design starts at the tetrahedral E4 4-and cubic E8 species, and we insert, respectively, six and twelve -conjugated linkers between the vertex atoms in the two structures. Carbon atoms were chosen at the vertices as they provide for stronger -conjugation than the heavier Group 14 elements which are found in tetrahedral Zintl ions earlier labelled as 3D-aromatic. For the tetrahedral species, we also considered N atoms at the vertices but they lowered the -electron delocalization (see Figure ). With four anionic sp 3 hybridized C atoms (tetrahedral species)