In the title compound, 4-nitro-7-oxocyclohepta-1,3,5-trienyl butanoate, C11
H11NO5, the tropolone ring is approximately perpendicular to the ester plan
e [dihedral angle 71.8 (1)degrees] and the paraffin chain has trans and gau
che conformations. Intermolecular pi-pi interactions between the tropolone
planes are observed in the crystalline state.