摘要： Devising sensors for perrhenate anion in aqueous media is extremely challenging, and is seldom reported in literature. Herein, we report a fluorescence turn-on sensor for perrhenate anion in aqueous medium based on the aggregation induced emission of a popular ultrafast molecular rotor dye, Thioflavin-T. The selective response towards perrhenate anion has been rationalized in terms of matching water affinity, where the weakly hydrated perrhenate anion spontaneously forms a contact ion-pair with the weakly hydrated ultrafast molecule rotor based organic cation, Thioflavin-T, which in turn leads to an aggregate assembly that provides a fluorescence turn-on response towards perrhenate. The sensing response of Thioflavin-T is found to be quite selective towards perrhenate anion, when tested against the anions which are ubiquitously present in the environment such as chloride, nitrate, sulphate etc. The formation of self-assembled Thioflavin-T aggregates has been also investigated by time-resolved emission and temperature dependent measurements.