The triarylphosphanes, (o‐thiomethylphenyl)diphenylphosphane (SP, 1), (o‐N,N′‐dimethylaminophenyl)diphenylphosphane (NP, 2), and (o‐methoxyphenyl)diphenylphosphane (OP, 3) have been structurally characterized. Detailed information on the stereochemistry of the ligands was gathered by spectroscopic (1H, 31P, 13C NMR) and X‐ray crystallographic studies. Molecular modeling methods for investigation of the structures were also applied. It is shown that the geometrical optimization of the ligand can be performed accurately by the ab initio Hartree−Fock method. Furthermore, the steric contribution of the coordinated ligands can be estimated by studying the different conformational states of the free ligands. The coordination abilities of the ligands were studied in reactions with the rhodium compounds Rh2(CO)4Cl2 and Rh(NO3)3 under different reaction conditions. The SP and NP ligands yielded mononuclear chelate complexes, while the OP ligand coordinated solely in a monodentate fashion through the phosphorus atom. The crystal structures of the ligands 1−3 and the rhodium(I) complexes [RhCl(CO)(NP)] (5) and [RhCl(CO)(OP)2] (6) are reported.