Coordination polymer of Cu(II) bridged by o-phthalic acid alone is not known. The reaction of CuCl 2 .2H 2 O with (2-butoxycarbonyl)benzoic acid yielded three dimensional coordination polymer bridged by o-phthalic acid. X-ray crystal structure shows structure with monoclinic P 2 1 /c space group. o-Phthalic acid molecules act as bridge between two Cu(II), one carboxylate binds to one Cu(II) as bidentate while the other carboxylate binds to another Cu(II) as monodentate. The four planar coordination positions of Cu(II) are satisfied by two chelated carboxylates while fifth and sixth coordination positions are satisfied by monodentate carboxylates. EPR and TGA of the coordination polymer are also reported.