Zinc(II) and copper(II) complexes of o-phthalic acid (H2phth) were synthesized by microwave solid-state method with o-phthalic acid, zinc acetate or copper acetate as raw materials. Chemical and element analysis, FT-IR, X-ray powder diffraction and TG-DTG analysis were applied to characterize the composition and structure of the compounds. The results show that the compositions of the complexes are Zn(phth)?2H2O and Cu(phth)?H2O, the ligand is coordinated simultaneity with Zn(II) or Cu(II) via the carboxyl group of o-phthalic acid to form bidentate chelates. Thermal decomposition processes of the complexes include dehydration, oxidation and pyrolysis of the ligand, and finally as metallic oxide.