Automated parallel synthesizers provide fast and comparable screening of different polymerization parameters under similar conditions. In addition, these robotic systems eliminate handling errors, which may affect the results of a kinetic experiment more than the effect of an important parameter. The polymerization temperature and N,N-tert-butyl-N-[1'-diethylphosphono-2,2-dimethylpropyl]nitroxide concentration were optimized for the homopolymerization of both styrene and tert-butyl acrylate to improve the control over the polymerization while reasonable polymerization rates were retained. Subsequently, polystyrene and poly(tert-butyl acrylate) macroinitiators were synthesized according to the knowledge obtained from the screening results. These macroinitiators were used for the preparation of block copolymers consisting of styrene and tert-butyl acrylate. (c) 2006 Wiley Periodicals, Inc.