Emission based response of highly luminescent carbozole derivative, 2(9-methyl-9H-carbazol-3-yl)-5-(pyridin-4-yl)-1,3,4-oxadiazole (ODC-3), to Hg(II) ions was investigated. The dye was encapsulated in ionic liquid doped ethyl cellulose (EC) matrix in form of nanofibrous materials and continuous thin films. The nanofibers were fabricated by electrospinning technique. The ratiometric response to Hg(II) ions was monitored at 418 nm and 505 nm. The quenching behavior follows Stern-Volmer quenching kinetics. The ODC-3 dye can be used for quantitative determination of Hg(II) in the concentration range of 1.0 x 10(-11)-1.0 x 10(-3) M. With respect to continuous thin films, the electrospun nanofibers offered enhanced sensitivity, lower LOD values and shorter response times in optical chemical sensing of Hg(II). (C) 2013 Elsevier B.V. All rights reserved.