Aza crown ether appended hetarylazo dye-single molecular dual analyte chemosensor for Hg2+ and Pb2+.

A hetarylazo dye appended with an aza crown ether detects and discriminates Hg(2+) and Pb(2+) from each other by immediate visual observation, significant from an 'on-site' evaluation point of view. It is accompanied by absorption based changes and is convincingly established from (1)H NMR, TD-DFT and electrochemical studies.