Synthesis and properties of novel fluorescent switches.

[reaction: see text] Photochromic dithienylethene moieties were covalently attached to fluorescent 4,4-difluoro-8-(4'-iodophenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (iodo-BODIPY) via a phenylacetylene linker. UV light induced isomerization of the photochrome results in significant decrease in fluorescence intensity. This fluorescence can be recovered with visible light.