Concentration effects on the fluorescence (FL) emission of 1, 3-dibenzoylmethanatoboron difluoride (1aBF2) and its diisopropyl derivative (1bBF2) in KBr and CH2Cl2 were investigated. Powder samples of 1aBF2 and 1bBF2 in KBr exhibit yellow and white FL emissions, respectively, whose intensities and wavelengths are not significantly affected by concentration. In contrast, remarkable concentration effects on FL properties of these ...