So far, very few numbers of chemosensors for Cr3+ ion have been reported. However, the main drawback of reported receptors are the lack of selectivity and other trivalent cations such as Fe3+, Al3+ and anions like F− and −OAc frequently interfere with such assays. This paper present the synthesis, characterization & sensor studies of Schiff base containing naphthalene moiety which selectively detect Cr3+ ion by chemodosimetric approach. Using FT-IR, 1H NMR, 13C NMR and ESI mass spectroscopic techniques the probe was characterized. This receptor exhibit more selectivity and sensitivity towards Cr3+ than other divalent and trivalent cations like Mn2+, Zn2+, Co2+, Ni2+, Cd2+, Cu2+, Hg2+, Fe3+, and Al3+ ions. After the addition of chromium ion the receptor get change from yellow to colorless in aqueous medium. But no color change was observed on the addition of other metal ions. Using UV-Vis and PL studies, it was confirmed that the selective hydrolysis of imine group of receptor by Cr3+ ions takes place with high fluorescence enhancement that is corresponding to 1-naphthylamine. Receptor acts as selective chemodosimeter for Cr3+ ions with 2:1 stoichiometry and micro molar detection limit. This chemodosimetric approach was applied successfully for bio-imaging of HeLa cells.