Coordinatively unsaturated rhodium and iridium complexes bearing a bulky thiolate ligand, [Cp*M(SDmp)](BAr F 4 ) (2a, M = Rh; 2b, M = Ir; Cp* = η 5 -C 5 Me 5 ; Dmp = 2,6-(mesityl) 2 C 6 H 3 ; Ar F = 3,5-(CF 3 ) 2 C 6 H 3 ) were synthesized from the reactions of [Cp*MCl] 2 (μ-Cl) 2 with LiSDmp and NaBAr F 4 . The metal centers in 2a and 2b weakly interact with the ipso-carbon of one of the mesityl groups in the SDmp ligand, while the ipso-carbon dissociates from the coordination sphere in the reactions with donor ligands. Treatment of 2a or 2b with 2,2 0 -bipyridine (bpy) or 1,10-phenanthroline (phen) led to the formation of [Cp*M(SDmp)(bpy)](BAr F 4 ) (3a, M = Rh; 3b, M = Ir) or [Cp*M-(SDmp)(phen)](BAr F 4 ) (4a, M=Rh; 4b, M = Ir), respectively. The reactions of 2a and 2b with 2 equiv of tert-butylisocianide or 1 atm of CO gave rise to the bis-adducts [Cp*M(SDmp)(L) 2 ]-(BAr F 4 ) (5a, M=Rh, L=CN t Bu; 5b, M = Ir, L = CN t Bu; 6a, M = Rh, L=CO; 6b, M = Ir, L = CO). The coupling of terminal alkynes and SDmp took place upon the addition of excess 1-pentyne or phenylacetylene to solutions of 2a or 2b, affording cationic complexes with an S-arylated thiophene group, [Cp*M(η 4 -2, 4-R 2 C 4 H 2 S-Dmp)](BAr F 4 ) (7a, M = Rh, R = n Pr; 7b, M = Ir, R = n Pr; 7c, M = Rh, R = Ph; 7d, M = Ir, R = Ph).