stimuli‐responsive chemical sensors. We designed a polysulfurated arene system based on a tetra(phenylthio)pyrene core decorated with four carboxylic acid units. Three different regioisomers, ortho , meta and para were studied in organic and aqueous solution. These systems are soluble in water at pH≥8 due to the deprotonation of carboxylic acids. The addition of metal ions cannot only quench the fluorescence