We designed a “turn-on” type fluorescent probe based on a BODIPY–pyridine conjugate which exhibits high selectivity towards Au(III) ions and, also responds to changes in the pH within the acidic pH range. The probe offers features such as a rapid response time, a low detection limit, and high sensitivity and selectivity. The detection of Au(III) is recognized by a distinct change in the emission intensity which relies on a reversible “ligand to ion” binding mechanism. We also document the utility of the probe for the quantification of gold ion residues in synthetic end products prepared via gold catalysis.