A series of ligands with site specific electron donating substituents that form a catalyst complex with a transition metal and are suitable for catalysis of atom transfer radical reactions, including ATRP are described. Faster catalysis rates were observed allowing for low catalyst concentrations and linear increases in molecular weight with monomer conversion, and narrow molecular weight distributions. Cyclic voltammetry revealed that increasing the strength and number of conjugated electron donating groups resulted in more stable complexes and larger ATRP equilibrium constants.