Tripodal imidazole containing ligands, bis((2-pyridyl)methyl)(1-methylimidazole-2-yl)methyl)amine (BPIA) and bis((1-methylimidazole-2-yl)methyl)((2-pyridyl)methyl)amine (BIPA), were synthesized and used for copper catalyzed atom transfer radical polymerization (ATRP) of n-butyl acrylate (nBA). The molecular weights of poly(n-butyl acrylate) (PnBA) catalyzed by CuBr/BPIA and CuBr/BIPA complexes increased linearly with nBA conversions and they were close to theoretical values with low polydispersities. ATRP equilibrium rate constant (K-ATRP) measurements showed that both CuBr/BPlA and CuBr/BIPA complexes had high K-ATRP values, similar to that of CuBr/tri(2-pyridylmethyl)amine (TPMA), which is one of the ATRP most active ligands. Activators regenerated by electron transfer (ARGET) ATRP of nBA with CuBr2/BPIA and CuBr2/BIPA complexes were also conducted and polymerization reached high nBA conversions, resulting in PnBA with low polydispersities. This suggests that the copper complexes with BPIA and BIPA were sufficiently stable and active to conduct ATRP when catalyst concentration was low. ARGET ATRP to form high molecular weight PnBA with CuBr2/BPIA and CuBr2/BIPA complexes was also successful. (C) 2008 Wiley Periodicals, Inc.