A class of heterocyclic compounds that include four or more fused rings. Both aromatic or non-aromatic ring structures are included in this category.

Synonyms: Heterocyclic Cpds, 4 Ring, Fused Heterocyclic Compounds, Five Ring, Heterocyclic Compounds, 5 Ring, Heterocyclic Cpds, 4 or More Rings, 5-Ring Heterocyclic Compounds, Heterocyclic Compounds, 4-Ring, Five Ring Heterocyclic Compounds, Heterocyclic Compounds with Four or More Rings, 0, Heterocyclic Compounds, 4 or More Rings, 4-Ring Heterocyclic Compounds, Fused Heterocyclic Compounds, Four-Ring, Fused Heterocyclic Compounds, Five-Ring, Heterocyclic Compounds, 4 Ring, Heterocyclic Cpds, 5 Ring, Fused Heterocyclic Compounds, Four Ring, Four Ring Heterocyclic Compounds, Heterocyclic Compounds with 4 or More Rings, Heterocyclic Compounds, 5-Ring