A new fluorophore pyrido[1,2-a]benzimidazole based ratiometric fluorescent probe for the selective detection of sulfite ions in water was investigated. It shows large (pseudo) Stokes shifts (260 nm), high FRET efficiency, high selectivity and sensitivity. A distinct color change from red to colorless was observed and importantly, it proves to be a convenient and efficient tool to detect the sulfite levels in sugar samples.