The unimolecular dissociation :reactions of energy-selected furfural cations have been studied by imaging photoelectron photoion coincidence spectroscopy at the vacuum-ultraviolet (VUV) beamline of the Swiss LightSource. In the, photon energy range of 10.9-14.5 eV, furfural ions decay by numerous fragmentation channels. Modeling the breakdown diagram yielded the 0 K appearance energies of 10.95 +/- 0.10, 11.16 and 12.03 eV for the c-C4H3O-CO+ (m/z = 95), c-C4H4O+ (m/z = 68), and c-C3H3+ (m/z = 39) fragment ions, respectively, formed by parallel dissociation-channels. An internal conversion from the A" to the A' electronic state via a conical intersection takes place along the reaction coordinate in the case of the H-loss channel (c-C4H3O-CO+ formation). Quantum chemical calculations and experimental results confirmed a fast conversion to the A' state and that the rate, determining step is a tight transition state oil the potential energy surface. Appearance energies were also derived for the sequential dissociation products from the furan cation, c-C4H4O+, for the formation of CH2CO+ (m/z = 42), C3H4+ (m/z = 40), and CHO+ (m/z = 29) at 12.81, 12.80, and 13.34 eV, respectively: Statistical rate theory modeling of the breakdown diagram can also behsecf to predict the fractional ion abundances and thermal Shifts in mass spectrometric pyrolysis studies to help assigning the m/z channels either to ionization of the neutrals or to dissociative ionization processes, with,potential use for combustion diagnostics. The cationic geometry optimizations yielded functional-dependent spurious DFT minima and a deviating planar MP2 optimized geometry, which are briefly discussed.