<p>A turn-off naphthalene-based Schiff base probe (E)-2-((2-hydroxy-4-sulfonaphthalen-1-yl) imino) methyl) benzoic acid (<b>HSMB</b>) was synthesized and used for the selective detection of Fe³⁺ ions in aqueous media. FTIR, elemental analysis and NMR was used for the characterization of probe. Excitation and emission bands at 346&#xa0;nm and 478&#xa0;nm shown by the probe were correlated with theoretical values of 227&#xa0;nm and 493&#xa0;nm respectively calculated by computational analysis. Time-Dependent Density Function Theory calculations revealed that intramolecular charge transfer was responsible for selective turn-off fluorescence behavior of the probe towards Fe³⁺ metal ions in water at neutral pH with limit of detection of 2.5µM. Association constant of 4 × 10³ M⁻¹ was determined through Benesi-Hildebrand equation and binding stoichiometry of metal-ligand complex was 1:1 in the Job’s plot analysis. The probe was very selective and efficient for the detection of Fe³⁺ ions in the presence of various metal ions in aqueous media without the bar of maintaining pH. In comparison to other methods like colorimetry, atomic absorption spectrometry, ion-pair chromatography etc. the synthesized Schiff base fluorimetric probe exhibited lower detection limit making it a potential candidate for practical applications.</p> Graphical Abstract <p></p>