A new multi-functional iniferter with photo-induced and thermal dissociation group in one molecule, diethyl 2,3-dicyano-2,3-di(p-N,N-diethyldithiocarbamylmethyl)phenyl-succinate(DDDCS), was successfully synthesized. The bulk polymerizations of styrene (St) with DDDCS were studied. The initiation can take place either under UV light irradiation by the reversible C-S bonds dissociation of DDDCS or under heating by the reversible hexa-substituted C-C bond thermally dissociation. The polymerizations have "living" polymerization characteristics under both cases, i.e., the yield and the molecular weight of the resulting polymer increased linearly with increasing reaction time, and the resultant polymers can act as macroiniferter for preparing block copolymer.