The syntheses of 2,5-dicyano-1,4-bis-(4'-methoxystyryl)benzene (MOS-CN), 2,5-dicyano-1,4- bis-(4'-dimethylaminostyryl)benzene (MAS-CN) and 1,4-bis-(4'-methoxystyryl)benzene (MOS) with typical D-A-D conjugation structure were reported. Their structures were characterized by ¹H NMR, IR and elemental analyses. Linear absorption, single-photon induced fluorescence, two-photon induced fluorescence and two-photon absorption cross section (σ₂) are experimentally studied. While pumped with 800 nm laser irradiation, these three compounds showed strong two-photon induced green, yellow and blue fluorescence, respectively. The maximum absorption wavelengths, single-photon emission wavelengths, two-photon induced fluorescence wavelengths, fluorescence quantum yields, two-photon absorption coefficients, two-photon absorption cross sections (σ₂) and two-photon fluorescence lifetimes of MOS-CN, MAS-CN and MOS were 393, 473, 367 nm; 470, 569, 434 nm; 475, 574, 438 nm; 0.12, 0.72, 0.21; 0.8, 5.3, 0.3 cm/GW; 270, 1790, 101 GM; 140 ps, 1.32 ns, 54 ps, respectively. The σ₂ of MAS-CN was 6.63 times that of MOS-CN, and σ₂ of MOS-CN was 2.67 times that of MOS, which manifested that a contraposition amino group could prominently improve the two-photon absorption ability of such D-A-D compounds, and cyano groups could also make a great contribution to σ₂ .

Key words: synthesis, two-photon absorption, upconversion fluorescence