Abstract: Starting from 3-acetylpyridine and diethyl oxalate, 3-pyridylformylpyruvic acid ethyl ester (HL) was prepared. The proton magnetic resonance spectroscopy implies that the ?-dione moiety of HL adopts the enol form. Its first coordination compound, CuL2n, was obtained through interface diffusion. The single crystal X-ray diffraction analysis shows that in the complex the Cu(II) atom is surrounded by four L ligands to form an elongated trans-CuN2(OO)2 octahedron. Each of the two crystallographically L ligands bites an Cu(II) atom via the two dionate O atoms and binds another Cu(II) atom via the pyridyl N atom simultaneously. Infinite connection of the Cu(II) atoms and the L ligands leads to formation of a two-dimensional network.