This thesis is a summary of the research conducted since September 1999 at the University of Toronto in the laboratory of Dr. Robert A. Batey. This manuscript is divided into four chapters. Chapter one provides a general introduction to the nature and reactivity of organo trifluoroborate salts. Their preparation from organoboron or organohalide precursors, as well as their use in a variety of synthetic transformations is reviewed. The preparation of novel tetra- n-butylammonium organotrifluoroborate salts within our own laboratory is also described. Chapter two provides an overview of the classical copper-mediated Ullmann Reaction for carbon-carbon bond formation between aryl halides, as well as modern variations of the Ullmann-Goldberg Condensation for carbon-oxygen bond formation. Our contributions to this area of synthetic chemistry are described, including the copper-catalyzed cross-coupling of potassium aryl- and alkenyltrifluoroborates with unactivated alcohols and phenols, which were achieved in good to excellent yields by utilizing copper acetate monohydrate as catalyst under an atmosphere of oxygen in the presence of 4A molecular sieves. Recent work into the copper-mediated/catalyzed cross-coupling of potassium organotrifluoroborate salts with activated carboxylate salts is also described. Chapter four describes our efforts in the investigation of the mechanism of the cross-coupling. The various stages of the catalytic cycle are examined with particular focus upon the oxidation state of the copper species involved. The role of molecular sieves in the transformation is also explored, as experimental observations have suggested that they play a greater part than just as desiccant in the reaction. Finally, the result of a short study on the phenomenon of the deactivation of the catalytic transformation by the presence of quaternary ammonium species is also presented. Chapter three describes modern approaches to carbon-nitrogen bond formation through the Ullmann-Goldberg Condensation of organometalloid species with nitrogen-based nucleophiles. The result of an investigation into the stoichiometric copper-mediated cross-coupling of potassium organotrifluoroborate salts and anilines is presented. In addition a novel reaction protocol for the ligandless and base free copper-catalyzed arylation of aliphatic amines is presented. The cross-coupling was found to work equally well with both potassium organotrifluoroborate salts and organoboronic acids.