Three compounds: 4-vinylpyridine-4-(N,N-diphenylamino)benzene(PPAB), Tris[4- (4-Pyridylethenyl)phenyl]amine (TPPA), 4-(N,N-diphenylamine)benzene -vinyl -1-methyl- pyridinium iodide(PBPI), were synthesized and characterized. The absorption and one-photon fluorescence properties have been investigated . Three-photon upconversion fluorescence spectra of these molecules were measured using a femtosecond Ti:sapphire. Large optical power limiting has also been demonstrated for the three compounds. Their three-photon absorption coefficients obtained by nonlinear transmission method are 1.91×10-79cm6s2, 3.46×10-79cm6s2, 3.64×10-79cm6s2 , respectively.

Key words: optical power limiting