X-ray, ultraviolet, and visible light induced photophysical changes of coumarin-540A in ethanol have been studied by the joint applications of X-ray, ultraviolet, and visible spectroscopy. Some impurities were found by X-ray fluorescence measurements. During the high power optical pumping, coumarin showed photochemical changes. Photoproduct emission spectra characteristics showed that photoproduct molecules can also be used as a laser dye at a different emission frequency in the ultraviolet region. (c) 2006 Elsevier B.V. All rights reserved.