alpha-Diazoketones undergo smooth coupling with aryl 1,2-diamines in the presence of 10 mol % of copper(II) triflate to provide the corresponding 2-alkyl- or 2-aryl-quinoxalines in excellent yields with high selectivity. Rh-2(OAc)(4) is also found to be an equally effective catalyst for this transformation. It is a new and alternative approach for the preparation of biologically well-defined quinoxaline derivatives.