Abstract The synthesis and full characterization of the water-soluble complex [Rh(μ-Pz)(CO)(TPPMS)]2 (I), where TPPMS is (C6H5)2P(m-C6H4SO3Na) and Pz pyrazolate, is described. Complex I was obtained by ligand exchange procedures under inert atmosphere and characterized by FT–IR, 1 H NMR, 1 H { 31 P } NMR, 31 P NMR and FAB-MS techniques. These analyses confirmed that there are two pyrazolate bridging ligands in an exobidentate orientation, giving a C2ν symmetry to the complex. The molecular weight of I was confirmed by FAB-MS, indicating the molecular formula stated above. The complex was active in the catalytic hydroformylation of 1-hexene and styrene in a two-phase reaction medium. Heptanal was the main product obtained for 1-hexene, while 2-phenylpropanal and 3-phenylpropanal were obtained from styrene. At the end of the reaction, all the metal remained in the aqueous phase, indicating that no metallic leaching observed during the catalytic reaction.