A series of thiophene tungsten Fischer carbene complexes of type [(CO) 5 W=C(OMe)R] (1, R = 2-Th; 3, R = fcthFc) and [(CO) 5 W=C(OMe)-R'-(OMe)C=W(CO) 5 ] (2, R' = th; 5, R' = fcthfc) was synthesized for investigating low energy charge transfer interactions between the carbene substituents and the transition metal carbonyl fragment incorporating the thiophene heterocyclic system (Th = Thienyl; th = 2,5-thiendiyl; Fc = ferrocenyl; fc = 1,1'-ferrocenediyl).Electrochemical investigations were carried out on these complexes to get a closer insight into the electronic properties of 1, 2, 4 and 5. They reveal reversible one-electron redox events for the 2 ferrocenyl moieties. Moreover, typical electrode reactions could be found for the carbene reductions itself and for the tungsten carbonyl oxidation processes. However, for the thiophene complex 2 two well-separated one-electron reduction events were observed. During the UV-Vis-NIR spectroelectrochemical investigations typical low energy absorptions for the mixed-valent α,α'-diferrocenyl thiophene increment were found, as well as high energy NIR absorptions, which were attributed to metal-metal charge transfer transition between the tungsten carbonyl increment and the ferrocenyl units in the corresponding species. Further infrared spectroelectrochemical studies reveal that the electronic interactions in the corresponding cationic species can be described with weakly coupled class II systems according to Robin and Day.