Fluorescent sensors capable of binding selectively and strongly to anions in water will provide innovative technologies for the detection of anionic species in a range of areas including environmental (e.g. monitoring of sulfate levels in wastewater) and biomedical applications (e.g. detection of chloride concentrations in blood). Currently available receptors are either limited to organic solvents or can not discriminate between anions. New hydrogen bonding motifs with proven ability to bind to ions anions in aqueous solution will be appended to water soluble dyes to provide fluorescent sensors. The molecular scaffolds will be tailored to match the size and shape of sulfate and chloride anions and their ability to selectively sense these anions will be evaluated. We will develop novel designs and methodologies to create sensors for anion binding in water that will underpin future applications.