Pyridinium functionalized derivative of tetraphenylethene with iodide ion as a counter anion was reported for highly selective detection of fluoride ion in aqueous media. Rapid "turn-on" fluorescence signaling with hypsochromic shift upon addition of micromolar quantities of fluoride ion to the aqueous solution of was attributed to the formation of aggregated amorphous tetraphenylethene units due to the decrease in solvolysis caused by the ion exchange process between fluoride and iodide ion. The ion-exchange induced emission formation due to the formation of less soluble amorphous salts is the novel approach for AIE active turn-on fluorescent sensing analysis. The experimental studies obviously demonstrate the selectivity of designed luminogen for fluoride ion detection when compared with other metals, particularly CN-, and AcO-. The practical applicability of the presented fluorometric method in tap water was also associated with satisfactory results. It is concluded that, such simple and convenient sensing strategy with a great potential for practical applications could provide a promising powerful tool for rapid, sensitive and selective analysis of fluoride ion. (C) 2015 Elsevier B.V. All rights reserved.