The crystal structure of the title compound, [C9H8NO]2[FeCl4]C1, has been determined by single-crystal X-ray diffraction methods at 295 K and refined by least squares to a residual of 0.043 for 2415 independent 'observed' reflections. Crystals are triclinic, P1, a 14.243(5), b 10.177(3), c 7.583(3) �, α 84.71(3), β 86.96(3), γ 86.50(3�, Z 2. The organic moiety is protonated at the nitrogen atom, with the discrete chloride ions hydrogen-bonded in lattice tunnels; this offers a rationale for the finite but small hydrogen chloride partial pressure at room temperature.