Two novel RAFT inimers, small molecule inimer 2-(methacryloyloxy)ethyl 4-cyano-4-(phenylcarbonothioylthio)pentanoate (MAE-CPP) and macro inimer PMMA-MAE-CPP were synthesized and used to prepare hyperbranched polymers via RAFT polymerization without the use of a divinyl cross-linker. The hyperbranched polymers synthesized included copolymers of MAE-CPP with styrene, copolymers of the macro inimer PMMA-MAE-CPP with styrene and the homopolymerization product of the macro inimer PMMA-MAE-CPP. The spectroscopic characteristics and polymerization kinetics of these RAFT polymers obtained under different polymerization conditions were systematically studied and the results compared with those obtained from the corresponding linear RAFT polymerizations as well as from hyperbranched polymerizations performed in the presence of a divinyl cross-linker which are reported in literature. The RAFT methodology reported here for the preparation of hyperbranched polymers is simpler than those reported previously using a divinyl cross-linker and provides good control over the hyperbranched polymers without the formation of insoluble gels. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.