The dimeric rhodium precursor [Rh(CO) 2 Cl] 2 reacts with two molar equivalent of 9,9-dimethyl-4,5bis (diphenylphosphino)xanthene [xantphos] (a), bis(2-diphenylphosphinophenyl)ether [DPEphos] (b) and their corresponding dioxide analogues xantphos dioxide (c), DPEphos dioxide (d) to afford the monoand dicarbonyl complexes of the type [Rh(CO)Cl(L)] (1a,1b) and [Rh(CO) 2 Cl(L)] (1c,1d) respectively, where L = a-d. The complexes 1a-1d have been characterized by elemental analyses, IR and NMR ( 1 H, 31 P and 13 C) spectroscopy, and the structure of the ligand d was determined by single crystal X-ray diffraction. 1a-1d undergo oxidative addition (OA) reactions with different electrophiles such as CH 3 I, C 2 H 5 I and I 2 to give Rh(III) complexes of the types [Rh(CO) y (COR)ClXL] {R = -CH 3 (2a-2d), -C 2 H 5 (3a-3d); X = I and y = 0, L = a, b; y = 1, L = c, d} and [Rh(CO)ClI 2 L] (4a-4d) respectively. Kinetic data for the reactions of 1a-1d with CH 3 I indicate a pseudo-first-order reaction. The catalytic activity of 1a-1d for the carbonylation of methanol to acetic acid and its ester was evaluated at different CO pressure 15, 20 and 33 bar at 130 β’ C and a higher Turn Over Number (TON) (679-1768) were obtained compared to that of the well-known commercial species [Rh(CO) 2 I 2 ] -(TON = 463-1000) in each case under the similar experimental conditions.