A new green solvent, cyclopentyl methyl ether (CPME), is used for the first time in solvent mixtures for the successful supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of both activated and non-activated monomers. The SARA ATRP of methyl acrylate (MA), glycidyl methacrylate (GMA), styrene (Sty), and vinyl chloride (VC) in CPME-based mixtures is studied and presents similar features to those reported in the literature using other SARA ATRP systems. Moreover, CPME-based mixtures are suitable solvents for the controlled SARA ATRP of MA using different SARA agents, such as Fe(0), Cu(0), or Na2S2O4. The chemical structure and the retention of the chain-end functionality of the polymers are confirmed by H-1 NMR and MALDI-TOF analyses and the preparation of a well-defined PMA-b-PVC-b-PMA triblock copolymer. The method reported here presents an additional improvement in the search for new ecofriendly ATRP systems. (c) 2015 Wiley Periodicals, Inc.