Gas-phase FeO+ can convert benzene to phenol under thermal conditions. Two key intermediates of this reaction are the [HO-Fe-C6H5]+ insertion intermediate and Fe+(C6H5OH) exit channel complex. These intermediates are selectively formed by reaction of laser ablated Fe+ with specific organic precursors and are cooled in a supersonic expansion. Vibrational spectra of the sextet and quartet states of the intermediates in the O-H stretching region are measured by infrared multiphoton dissociation (IRMPD). For Fe+(C6H5OH), the O-H stretch is observed at 3598 cm−1. Photodissociation primarily produces Fe++C6H5OH; Fe+(C6H4)+H2O is also observed. IRMPD of [HO-Fe-C6H5]+ mainly produces FeOH++C6H5 and the O-H stretch spectrum consists of a peak at ∼3700 cm−1 with a shoulder at ∼3670 cm−1. Analysis of the experimental results is aided by comparison with hybrid density functional theory computed frequencies. Also, an improved potential energy surface for the FeO++C6H6 reaction is developed based on CBS-QB3 calculations for the reactants, intermediates, transition states, and products.