A novel hybrid of azacrown ether-oxabridged fluorogenic chemosensor (L1) has been synthesized: the metal ion binding ability of the hybrid molecule shows higher affinity towards transition metal ion Zn2+ and heavy metal ion Hg2+ compared to the parent azacrown ether which shows poor metal ion selectivity: the binding modes of the Zn2+ and Na+ towards L1 have been discussed. © The Royal Society of Chemistry 2009.