The reaction of [RhCp(coe) 2 ] (1, coe = cis-cyclooctene) with one equivalent of the secondary phosphines PR 2 H in refluxing toluene afforded in situ the new complexes [RhCp(coe)(PR 2 H)] (R = Ph, 2a; R = o-tolyl, 2b; R = tBu, 2c) in good yields. Further thermolysis of 2a and 2b, respectively, in refluxing xylene resulted in the formation of the dinuclear doubly phosphanyl-bridged rhodium(II) species [{RhCp(μ-PR 2 )} 2 ] (3a and 3b). This thermolytic approach does not work in the case of 2c since the tBu substituents increase the electron density on the rhodium center and impede, therefore, the loss of the [a]