Activation of diazirine 1 with long-wavelength light, in the presence of cyclohexane, leads to C-H insertion of unactivated aliphatic bonds. successful photo-activation documented above, suggested the intriguing possibility that we might be able to activate compound 1 using red light. We therefore irradiated a capillary containing a solution of 1 in cyclohexane, in a two-photon microscope equipped with an 815 nm laser. The laser power was set low enough to avoid any unwanted heating of the sample (confirmed by the absence of cyclohexane evaporation under the conditions of the experiment).