A mixed bidentate ferrocenyl ligand Fe(η5-C5Me4P(S)Ph2)(η5-C5Me4PPh2) (abbreviated {P,PS}) was synthesised and used for complexation with [RhCl(CO)2]2. The neutral [4]-ferrocenophane {P,PS}Rh(CO)Cl 2 and the unusual dimeric cationic species [{P,PS}Rh(CO)(μ-Cl)(CO)Rh{P,PS}]+ 3 were obtained and characterized by crystal structure analysis. During investigations on the catalytic properties of 2 in carbonylation, some aspects of its behavior towards iodomethane were elucidated.