The reaction of the differently substituted cyclopentadienyl complexes L2M2(CO)4 with sulfur is investigated with respect to the ligand L (etmcp = ethyltetramethylcyclopentadienyl, tbcp = t-butylcyclopentadienyl, ipcp = isopropylcyclopentadienyl) and the metal M (Cr, Mo, W). For M = Cr the only isolated product is etmcp2Cr2S5. For M = Mo three isomers A, D, E of composition L2Mo2S4 (L = ipcp, etmcp) are formed whereas only two isomers (A, D) exist for L = tbcp. Only two isomers (D, E) of composition L2W2S4 are formed in the system L2W2(CO)4/S8, a further product is L2W2(CO)2S3 for L = etmcp. Structural characterisation of all compounds was achieved by IR, H-1, and Mo-95 NMR spectroscopy, whereas the structures of syn-etmcp2M2(mu-S)2S2 (M = Mo, W) were determined by X-ray crystallography, the result of which allows the correction of a previous structure assignment. It is further shown that a thermal equilibrium exists between L2Mo2(mu,eta-2-S2)(mu-S)2 (A) and syn-L2Mo2(mu-S)2S2 (D) which depends strongly on the ligands.