The processing of polymer solutions into nanofibers by meansof electrospinning is a rather straight-forward, reliable, and scal-able process, requiring relatively low cost equipment. A remarkablenumber of polymers can be electrospun to nanofibers and an inter-ference of the spinning process due to the addition of a fluorescentdye has not been observed. Typical polymer–dye formulations usedfor polymer films in conventional opto-chemical sensor systemsmay therefore be spun to highly porous fluorescent polymer fleeceswith only a few optimization steps, resulting in vastly acceleratedresponse dynamics. Such nano-structured sensors show the sameoptical properties as the corresponding polymer film sensors andcan therefore act as an improved replacement in standard opto-electronic sensor setups.