Simple aromatic rings are aromatic organic compounds (also known as arenes or aromatics) that consist only of conjugated planar ring systems with delocalized pi electron clouds instead of discrete alternating single and double bonds. Typical simple aromatic compounds are benzene and indole.
Polycyclic aromatic compounds can be found in Category:Polycyclic_aromatic_compounds.
Polycyclic aromatic hydrocarbons can be found in Category:Polycyclic_aromatic_hydrocarbons.