A water-soluble supramolecular structured photosensitive initiator (SSPI) was developed by the supramolecular self-assembling between the photosensitizer (xanthene dye) and the initiator (Complex A). The structure of SSPI was characterized by static and dynamic fluorescence quenching method. The photolysis properties of SSPI in the film were evaluated. The photopolymerization of AM and bis-AM in the film using the SSPI as the photoinitiator was also carried out. The results indicated that the SSPI formation played an important role in the photolysis and photopolymerization process. The SSPI was an efficient water-soluble photosensitive initiator. (C) 2009 Elsevier Ltd. All rights reserved.