Two-photon absorption chromophores with a tunable [2,2′]bithiophene core

Two-photon absorption (TPA) chromophores were synthesized by sequential reactions of 3,5,3′,5′-tetrabromo-[2,2′]bithiophene with different terminal alkynes possessing electron donor and/or acceptor. Their TPA cross-section can be fine-tuned by the substitutents.