The degradation of iminodiacetic acid photoinduced (λexc =365 nm) by complexation with iron (III) in aqueous solution leads to the formation of iron (II) and formaldehyde with a quantum yield equal to 0.2. The addition of copper (II) to iron (III) iminodiacetate solution makes the process less efficient. A decomplexation process is observed that leads to the formation of copper (II) iminodiacetate whose absorption is strongly shifted toward shorter wavelengths.