This paper reports the use of laser flash photolysis (LFP) techniques to show that cyclohexadienyl cations (σ complexes) of the Friedel-Crafts reaction of 1, 3- dimethoxybenzene and the diphenylmethyl cation rearrange on the ns time scale without separating the aromatic compound and the electrophile. This is demonstrated through a study of the photochemical behaviour of 2-diphenylmethyl-1, 3-dimethoxybenzene (4) in 1 ...