Abstract Two new copper complexes [Cu(Hdpa)2(en)] (1) and [{Cu2(l-na)4(CH3OH)2}2CH3OH] (2) (where en is ethylene diamine, Hdpa is 20-carboxy-[1,10-biphenyl]-2- carboxylate anion and na is 1-naphtalenecarboxylate) have been synthesized and their crystal structures were determined by X-ray crystallography. Complex 1 was prepared from the reaction of Cu(NO3)23H2O with ethylene diamine and 2,20-biphenyldicarboxylic acid in a mixture of water and methanol and complex 2 was prepared from the reaction of CuSO45H2O with 1-naphtalenecarboxylic acid in methanol. The two complexes were characterized by IR, UV–vis, luminescence and elemental analysis. Moreover, complex 2 was characterized by EPR spectroscopy and thermogravimetric analysis. Complex 1 is a monomer and complex 2 is a dimer with a paddle-wheel structure; both structures are without precedent in the literature.
