Solutions of copper(II) salts and excess 2,9-dimethyl-1,10-phenanthroline (dmp) in organic solvents yielded complexes of formula Cu(dmp),X,.H,O, where X=NO3, Cl, and Br. When excess of the copper(II) salt was present, mono complexes represented by CudmpX2, where X=NO3, Cl, Br ; 2X=SO4 were obtained. Copper(II) perchlorate-dmp mixtures yielded hydrated Cu(dmp),(ClO4)2. Aqueous solutions of the bis complexes changed colour when boiled and deposited red crystals of composition Cu(dmp)2X, with water of crystallization in some cases. Bis(dmp)copper(I) nitrate, perchlorate, and sulphate were also produced by reduction of the copper(II) complexes with hypophosphorus acid or hydroxylamine salts. The visible absorption curves for solutions of the complexes Cu(dmp)2X, corresponded with those reported in studies of the spectrophotometric estimation of copper using dmp. Mono complexes of formula CudmpX, where X=Cl, Br, and I, were prepared by reduction of the corresponding copper(II) complexes.