The first examples of CS induced PausonâKhand type reactions are described; 2-alkynylphenyl isothiocyanates were converted to 3-substituted-2H-thieno[2,3-b]indol-2-ones in the presence of a stoichiometric amount of Mo(CO)6 or Co2(CO)8, or a catalytic amount of Rh catalyst under an atmospheric pressure of carbon monoxide.