Photophysical and density functional studies on a nitrobenzoxadiazole-based system, N-butyl-7-nitrobenzo[c] [1,2,5] oxadiazol-4-amine (NBDH), have been investigated with a view to obtain molecular level understanding of the mechanism of interaction of inorganic anions with NBDH. The emission spectrum of the system exhibits large quenching of fluorescence on addition of F-. No appreciable changes in the absorption and fluorescence behavior of the present systems have been found in the presence of other anions. NMR investigation and theoretical calculations reveal that abstraction of acidic proton (N-H) ofNBDHby F- is primarily responsible for fluoride ion selective signaling behavior of the present system. (C) 2012 Elsevier B.V. All rights reserved.