Very few examples of butadienyl phosphines are described in the literature. In the context of our studies on highly nucleophilic metalated ylides, we recently discovered a new, general, one-pot synthetic route to prepare these potential ligands. The first example of a catalytic reaction using butadienyl phosphines is thus described. We found that 4-phenyl-1,3-butadienyldiphenylphosphine 4 is indeed an excellent ligand for Ullmann-type copper catalyzed arylations of N- and O-nucleophiles. Moreover, by following the reactions using ³¹P NMR, we are also able to propose a mechanism.