End-functionalized polystyrene (PSt) was synthesized via atom-transfer radical polymerization (ATRP) by using 4-chloromethyl benzoic acid (CMBA) and the ethyl-protected carboxylic acid, ethyl 4-chloromethybenzenecarboxylate (ECBC), as initiators respectively. The structure of PSt proved the living-radical polymerization. Results exhibit both ATRP initiators afforded well-controlled polymerization with high initiator efficiencies. However, the study also shows the controllability of ATRP can be obviously influenced by using different initiator in different catalyst system. Furthermore, the terminal group of the PSt1, benzoic acid, can coordinate with Europium(III) ion to obtain the polymeric Eu(III) complex, which shows both emissions of polymer and Eu(III) ion. (c) 2007 Wiley Periodicals, Inc.