In the title salt, C(2)H(8)N(+)·C(11)H(7)O(5) (-), the acetate group is twisted out of the plane of the coumarin ring system with a C-O-C-C torsion angle of 76.3 (2)°. In the crystal, N-H⋯O hydrogen bonds link the cations and anions into chains propagating in [100].