Published by ELSEVIER B.V. The meso-acrylic 1,3,5,7-tetramethyl-BODIPY derivative was obtained from 2,4-dimethylpyrrole and ethyl 4-chloro-4-oxobutanoate and its crystal structure was characterized by X-ray diffraction. This 8-alkenyl-BODIPY dye is originally nonfluorescent, but turns-on fluorescence upon the double bond reduction.