The complexes CpCo(CO) 2 (Cp = C 5 H 5 , C 5 H 4 Me, C 5 Me 5 and C 5 Ph 5 ) (1a -d) react with thiirane C 2 H 4 S under UV-irridiation in THF to form the dinuclear µ 2 -1,2-ethanedithiolate-S,S complexes [(CpCo) 2 (µ 2 -S 2 C 2 H 4 )] (2a -d) as main products. Using column chromatography, in case of Cp = C 5 H 5 Me also the dimeric complex [C 5 H 4 MeCo(µ 2 -S 2 C 2 H 4 )] 2 (3b), in case of Cp = C 5 Ph 5 the mixed disulfido-sulfido complex [(C 5 Ph 5 Co) 2 (µ 2 -S 2 )(µ 2 -S)] (4d) were isolated in small yields. Only 2a reversibly adds SO 2 gas to form the µ 2 -SO 2 complex [(C 5 H 5 CoSCH 2 ) 2 (µ 2 -SO 2 )] (5a). A bromo ligand bridging the Co atoms can be introduced by the reaction of [(C 5 Me 5 CoBr 2 )] 2 (6c) with 1,2-ethanedithiol which gives the cationic complex [(C 5 Me 5 CoSCH 2 ) 2 (µ 2 -Br)] 2 CoBr 4 (7c). All compounds have been characterized by their IR, 1 H and 13 C NMR and MS spectra and compounds 2b -d, 3b and 7c by X-ray structure analyses, which prove the pseudo tetrahedral skeleton (CpCoS) 2 and the ethane bridge between both sulfur atoms. 3b shows, however, a new unsymmetrical bonding mode of both dithiolato bridges with η 1 -S und µ 2 -S ligand functions.