Abstract Selective mercuration at the 1, 6-positions of 2-hydroxy derivative of Nile Red and its application towards-selective signaling was investigated. The 2-hydroxy Nile Red exhibited a selective UV-vis absorption and fluorescent signaling behavior towards ions over common coexisting physiologically important metal ions in aqueous environment. NMR studies revealed that the mercuration was selectively effected at the 1, 6-positions of 2- ...