Dioxins
Furans
Azoles
Thiophenes
Pyrans
Oxepins
Azolines
Azines
Azepines
Dihydropyranes
Oxygen heterocycles | Sulfur heterocycles
Unsaturated compounds
Thiines
Unsaturated sulfur heterocycles
Dihydrothiepines
Thiepines
Dihydroazines
Xanthenes
Nitrogen heterocycles
Dihydrofurans
Tetrahydroazines | Azirines
Unsaturated oxygen heterocycles
Pyrylium ion
Heterocyclic compounds
Phthalocyanines
Thioxanthenes
Oxazepines |