A molecular dual fluorescence-ON probe for Mg2+ and Zn2+: Higher selectivity towards Mg2+ over Zn2+ in a mixture

•A Schiff base incorporating a coumarin fluorophore has been synthesized.•It acts as a dual analyte sensor and quantifies Mg2+ and Zn2+ ions by emission enhancement at different wavelengths.•It shows excellent selectivity for Mg2+ ion in presence of alkali, alkaline earth metals as well as first row transition metals.

A Schiff base incorporating a coumarin fluorophore has been synthesized from easily available materials and is characterized by X-ray crystallography and other techniques. The probe serves as a dual analyte sensor and quantifies Mg2+ and Zn2+ ions by emission enhancement at different wavelengths without interference from a host of biologically relevant alkali/alkaline earth and transition metal ions. In presence of Mg2+ the light yellow color of the probe in methanol changes to yellow-orange while in presence of Zn2+ ion it changes to orange and hence can be detected through naked eye. The probe selectively gives emission of Mg2+ when Zn2+ ion is also present.