Circulene

A circulene is a macrocyclic arene in which a central polygon is surrounded and fused by benzenoids.

[1] Nomenclature within this class of molecules is based on the number of benzene rings surrounding the core, which is equivalent to the size of the central polygon.

The helicenes are a conceptually related class of structures in which the array of benzene rings form an open helix rather than a closed ring.

[8][9][10] A heterocyclic circulene is one in which the fused rings around the periphery are not simple hydrocarbons, but instead contain at least one other element.

Sulflower is a stable heterocyclic octacirculene based on thiophene.