PPV derivatives containing electron-donating and electron-withdrawing group attached stilbene moiety, poly[2-methoxy-5-(2-phenylethenyl)-1,4-phenylenevinylene] (PMPEPV), poly[2-(2-phenyl ethenyl)-1,4-phenylenevinylene] (PPEPV), poly[2-(2-(4-cyanophenyl)ethenyl)-5-methoxy-1,4-phenylenevinylene] (PCEMPV) and poly[2-(2-(4-trifluoromethyl)phenyl)ethenyl-1,4-phenylenevinylene] (PFEMPV) were synthesized through a water-soluble precursor polymers, and their third-order nonlinear optical susceptibilities were determined by using third-harmonic generation measurement technique at 1907 nm, fundamental wavelength. The measured chi((3)) values of PMPEPV, PPEPV, PCEMPV and PFEMPV were 2.1 x 10(-12), 1.7 x 10(-12), 1.2 x 10(-12) esu and 0.9 x 10(-12) esu, respectively.