Organolithium/cuprum diphenylphosphide (Ph2PCu) was used as a novel initiator to polymerize methyl methacrylate (MMA) and styrene in tetrahydrofuran (THF) at -50 to -10 degrees C. The polymerizations initiated by n-BuLi/Ph2PCu, Ph2PCu/Li (Ip)3-6Li/Ph2PCu, and PSLi/Ph2PCu were studied in detail. The polymerization of alkyl methacrylate initiated by n-BuLi/Ph2PCu showed a narrow molecular weight distribution (MWD) (1.081.25) and 100% initiation efficiency. The experimental number average molecular weight increased linearly with increasing [MMA]/[n-BuLi/Ph2PCu]. After the second monomer addition, the molecular weight increased proportionally while the MWD remained constantly narrow. These results reveal partial living characteristics. Ph2PCu/Li (Ip)3-6Li/Ph2PCu showed a similar behavior and was used to prepare PGMA-b-PBMA-b-PMMA-b-PBMA-b-PGMA successfully. The initiation efficiency of n-BuLi/Ph2PCu for styrene was low. The macromolecular initiator PSLi/Ph2PCu was prepared and PS-b-PMMA with a narrow distribution was synthesized. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012