A general method for the coupling of aryl and vinyl halides with diaryl and dialkyl phosphines, as well as with dibutyl phosphite, is reported. This highly efficient transformation is realized through the use of copper(I) iodide as a catalyst, N,N'-dimethylethylenediamine as a ligand, and Cs2CO3 as a base. A variety of sterically hindered and/or functionalized substrates were found to react under these reaction conditions to provide products In good to excellent yields.