The redox chemistry and pharmacological studies of the novel blue ruthenium(III)-catecholamine complexes were investigated in aqueous medium and compared to the free catecholamines. The [Ru(III)(NH3)4(catecholamine)]+ can be oxidized or reduced reversibly in one electron redox couples in aqueous solution. This is in contrast to the free catecholamines, which has a complicated electrochemical behavior due to coupled protonation process. The introduction of the ruthenium group reduces the intrinsic efficacy of the studied catecholamines. The [Ru(III)(NH3)4(catecholamine)]+ complex aqueous medium is more stable than the free catecholamines ligand in the same conditions.