The title compound, C(12)H(7)N(2)O(2) (+)·Cl(-), is isostructural with its bromide analogue. The compound exhibits a layered structure in which all atoms lie on a crystallographic mirror plane. N(+)-H⋯Cl(-) hydrogen bonds, C-H⋯O and C-H⋯Cl(-) contacts are formed within each layer. The perpendicular separation between the layers is 3.141 (1) Å.