Polyarylene ether nitrile (PEN) is traditionally used as high performance thermoplastics in various advanced engineering materials fields. However, the preparation of optically active PEN based materials, especially in aqueous solution, is still a great challenge. In this work, the side chain carboxylated PEN can be readily dissolved in alkaline solution but showing strongly quenched luminescence. Fortunately, the cationic surfactant of cetyltrimethylammonium bromide (CTAB) was able to recover the fluorescence emission of water soluble PEN, which can be subsequently quenched by Fe3+ ions, leading to the selective determination of Fe3+ ions in aqueous solution. (C) 2017 Elsevier B.V. All rights reserved.