The polymerization of n-butyl acrylate in the presence of two cyclic trithiocarbonates (CTTCs) and the synthesis of multiblock poly(n-butyl acrylate) have been investigated. The CTTCs not only can be stepwise incorporated into the polymer chain via reversible addition-fragmentation chain transfer (RAFT) but also can be polymerized into polytrithiocarbonate, which functions as a macro-RAFT agent in turn. Through two kinds of mechanisms, multiblock poly(n-butyl acrylate) containing narrow-polydispersity blocks can be prepared. (c) 2006 Wiley Periodicals, Inc.