Dissociation of the chlorobenzene molecular ion has been investigated on a nanosecond time scale by photodissociation mass-analyzed ion kinetic energy spectrometry. The present rate-energy data together with the previous microsecond data have been compared with theoretical results. A thermochemically reasonable analysis requires that the reaction occurs via a non-totally loose transition state. The Delta H-f0(o)(C6H5+) of 1141 kJ/mol, which leads to a 3.29-eV energy barrier for this reaction, allows consistent and successful analysis of rate-energy data for dissociations of chloro- and iodobenzene ions. It has been confirmed that transition-state switching (TSS) does not occur at high internal energy for these reactions. Possible occurrence of TSS near the threshold is also discussed.