Giant thienylene-acetylene-ethylene macrocycles with large two-photon absorption cross section and semishape-persistence

Giant pi-conjugated macrocycles composed of thiophene, acetylene, and ethylene subunits arranged as 72 pi, 108 pi, 144 pi, and 180 pi electron systems were synthesized and analyzed for their one- and two-photon absorbance properties. Increasing pi-conjugation showed an increase in the two-photon absorption cross section with magnitudes as high as 100 000 GM in the visible spectral region.