We synthesized 2-amino-1,3-propanediol-modified boron dipyrromethene (BODIPY) in a rapid two-step synthesis. The resulting fluorophore's emission was significantly quenched by polar solvents, but increased fourfold upon the addition of Hg2+ ions. Notably, this BODIPY fluorophore exhibited high selectivity toward Hg2+ ions over various other metal ions (Li+, Na+, K+, Ca2+ Co2+, Cu2+, Ni2+, Pb2+, Zn2+, Mn3+, Ag+, and Fe3+), with a binding constant of 7.36 × 104 M−1. The binding mechanism was investigated using proton nuclear magnetic resonance and infrared spectroscopy and revealed that 2-amino-1,3-propanediol moieties chelated the Hg2+ ions. These chelated Hg2+ ions could be replaced by the hexadentate EDTA molecules. Furthermore, treating BODIPY with an acid restored fluorescence emission, while a base diminished it, and this process was reversible. This rapidly synthesized BODIPY fluorophore holds great potential for Hg2+ ion detection.