4-Dimethylamino-2',5'-dihydroxychalcone (DMADHC), a typical compound that exhibits excited-state intramolecular charge-transfer (ICT) characteristics and possesses good photo-physical properties, is synthesized and used as fluoroionophore for a Fe3+ sensitive optochemical sensor. The sensor shows a linear response toward Fe3+ in the concentration range of 3.984 x 10(-7)-1.135 x 10(-5) M with a limit of detection of 8.223 x 10(-9) M. It exhibits excellent selectivity for Fe3+ over a large number of cations such as alkali, alkaline earth, and transitional-metal ions.