The syntheses and molecular structures of two novel polynuclear copper(I)-purine-phosphine complexes are reported. The first one is a dinuclear [Cu-2(mu-HL(1))(2)(mu-dppm)(eta(1)-dppm)(2)] complex (H(2)L(1) is 8-mercaptotheophylline). The compound crystallizes in the triclinic system, space group , with cell constants a = 12.342(5) Angstrom, b = 15.255(5) Angstrom, c = 24.972(5) Angstrom, alpha = 74.31(2)degrees, beta = 78.62(2)degrees, gamma = 72.51(2)degrees, and Z = 2. The structure of this complex exhibits as the most important feature the simultaneous presence of eta(1)-terminal and eta(2)-bridging dppm ligands, which is first here described for a copper complex. This complex is also of interest because of its reversible photochromic behavior in the solid state. The second compound is an ionic {[Cu-3(mu(3)-Cl)(2)(mu-dppm)(3)][Cu(HL(2))(2)]} complex (H(2)L(2) is 8-ethyl-3-methylxanthine), which crystallizes in the monoclinic system, space group P2(1)/n, with cell constants a = 15.829(6) Angstrom, b = 22.801(7) Angstrom, c = 28.569(6) Angstrom, beta = 97.65(4)degrees, and Z = 6. The structure of this complex consists of trinuclear copper(I) cations and mononuclear [Cu(purine)(2)](-) anions, exhibiting a linear stereochemistry. As far as we know, this compound represents the first example of a copper(I)-purine complex whose structure has been determined by X-ray crystallography.