Blue crystals of [Cu(phen)(C10H16O4)] · 3 H2O were grown by evaporation of a CH3OH/H2O solution containing CuCl2 · 2 H2O, 1,10-phenanthroline (phen), sebacic acid and Na2CO3 at 55 °C. In the crystal structure (triclinic, P 1 (no. 2), a = 10.988(1), b = 11.121(1), c = 11.200(2) Å, α = 110.64(1)°, β = 110.51(1)°, γ = 95.42(1)°, Z = 2, R = 0.0793, wR2 = 0.1566 for 3848 observed reflections), the Cu atoms are square-planar coordinated by the two N atoms of the phen ligand and two cis-O atoms of two bidentate bridging sebacate ligands with d(Cu–N) = 2.004(4), 2.015(4) Å and d(Cu–O) = 1.949(4), 1.953(3) Å. The sebacate ligands connect the Cu atoms to 1 D [Cu(phen)(C10H16O4)2/2] zigzag chains with the phen planes roughly parallel to the chain. By π-π stacking interactions between quinoline fragments of the phen ligands (3.38 Å spacing), two adjacent chains are combined to 1 D supramolecular [Cu(phen)(C10H16O4)2/2]2 double-chains along [111]. Uncoordinated H2O molecules are placed in voids.