Oxidation of styrene is carried out by using heptamolybdate coordinated transition metal (Co²⁺, Zn²⁺) complexes, [2-ampH]₄[{Co(H₂O)₅}Mo₇O₂₄]·9H₂O (1), [3-ampH]₄[{Co(H₂O)₅}Mo₇O₂₄]·9H₂O (2), [2-ampH]₄[{Zn(H₂O)₅}Mo₇O₂₄]·4H₂O (3) and [3-ampH]₄[{Zn(3-ampy)(H₂O)₄}Mo₇O₂₄]·4H₂O (4) as catalysts and H₂O₂ as an oxidant at 80°C. The leaching study has been carried out to check the quality of catalyst and it has been reused for three times with good percentage of conversion. For the first two catalysts (compounds 1 and 2), the major product obtained is benzaldehyde, and benzoic acid is the major product for next two catalysts (compounds 3 and 4). Stability of the catalysts has been analyzed by IR, UV-spectroscopy and powder X-ray crystallography.