FRET-based fluorogenic substrates for lipases and esterases were prepared in four steps from commercially available building blocks. The substrates are pyrenebutyric acid monoesters of aliphatic 1, 2-diols bearing a dinitrophenylamino group as a quencher. The most enzyme-reactive substrate is ester 2a. The substrates do not show any measurable background reaction in the absence of enzyme even at pH 11, but react fast and ...