Tolylphosphines, P(o-tolyl)(n)Ph3-n have been used in the palladium catalyzed Suzuki cross-coupling reactions of a series of aryl-bromides, chlorides and also two bromoarylphosphine oxides and a bromoarylphosphine with arylboronic acids. The effects of the phosphine, palladium source, base, solvent and promoter salt were investigated. In all studied phosphines, particularly P(o-tolyl)(n)Ph high conversions and turnovers were seen compared to ortho-unsubstituted phosphines which indicates that other factors such as cyclometallation in addition to steric and electronic effects may be responsible. (C) 2007 Elsevier B.V. All rights reserved.