Fluorescence emission spectra of DB-67 in ethanol-water mixtures starting from 100% ethanol as the solvent and changing to 100% water as the solvent. The % (v/v) ethanol in ethanol/water mixtures used to generate the displayed spectra in the figure are 100%, 97.5%, 95%, 90%, 50%, 25% and 0%, respectively. The decrease in the percent of ethanol is characterized by the decrease in the emission intensity at 430 nm and increase in the intensity at 560nm.