Namocomposites of benzo 15-crown-5 ether substituted oligo phenylene vinylene (CE-OPV) were prepared by solution intercalation into a surface treated bentone clay, B34, in both the presence and absence of Eu3+ ions, and were characterized using X-ray diffraction (XRD) and fluorescence techniques. The intercalation of B34 by CE-OPV increases the d-spacing (gallery height) of B34, the increase being more in the presence of metal ion than in its absence. The increase in d-spacing of a related material. poly[1,4.-(2,5-bis (tetra ethylene oxide substituted)) phenylene vinylene (EO-PPV)] due to intercalation into clay is greater than that by CE-OPV. Results on intercalation of small benzo-crown ether molecules themselves into B34 in the presence and absence of Eu3+, are also presented to help elucidate the process. The fluorescence emission maxima of the nanocomposites of CE-OPV, CE-OPV-Eu3+ and EO-PPV showed a steady blue shift as a function of B34 composition and the results are explained in terms of partial intercalation of the fluorophores into the clay. (c) 2005 Elsevier Ltd. All rights reserved.