procedures have been developed to prepare on a medium scale several phototoxic 2,2′:5′,2″-terthiophene derivatives of general formula 2 and 3, which are characterized by a functional substituent in the 3′- or the 5-position.Most of these procedures, which are based on the construction of the 2.2′:5′,2″-terthiophene moiety and involve palladium-mediated carbon-carbon bond forming reactions, allow to