[{"from": "human", "value": "Describe this molecule. [C][C][=C][C][=C][C][=C][C][=C][Ring1][=Branch1][Ring1][=Branch2]"}, {"from": "gpt", "value": "The molecule is a flammable polycyclic hydrocarbon. It is composed of a benzene ring fused with a cyclopentene ring. This aromatic liquid is colorless although samples often are pale yellow. The principal industrial use of indene is in the production of indene/coumarone thermoplastic resins."}]