Likewise, substrates 8, 13, and 24, required weaker acid (3:7, CF3CO2H:CF3SO3H) to promote the spiro cyclizaLons. This may be a consequence of the stronger acid, 100% CF3SO3H, protonaLng the aryl group -rendering it less reacLve as an internal nucleophile for the cyclizaLon. Thus for AbsorpLon and emission spectroscopy was done on all fully conjugated spirocycle products . For each tested compound, spectra showed the emission characterisLcs of the two disLnct chromophores. The fluorenyl chromophores' emission maxima were consistently observed at ~295 nm, and all of the aryl imidazole Scheme 2.