The appearance of a fluorescence emission band at 553 nm from hydrocarbon solutions of 4-N,N-dimethylamino-2′-hydroxychalcone was found to be sensitive to the presence of dissolved oxygen and exposure to ambient visible light. The 390 nm peak of this band's excitation profile along with the fluorescence maximum suggest that a low yield photoreaction occurs leading to the formation of the highly fluorescent 4′-N,N-dimethylamino-3-hydroxyflavone.