Poly(triethyldipropargylphosphonoacetate) (TDPA), poly[(tetraethyl dipropargylmethylenediphosphonate) (TDMDP) were prepared by metathesis polymerization using transition-metal catalysts. MoCl5-based catalyst systems were more effective for the polymerization of these monomers than WCl6-based catalyst systems. Resulting polymers exhibited good solubility in common organic solvents and could be easily cast on glass plates to give thin films. Third-harmonic Maker fringe technique was used to measure third-order nonlinear susceptibility, chi(3), for thin film of poly(TDPA). The chi(3) was evaluated to be 3.4 x 10(-11) esu at incident wavelength of 1.907mum.