Two enantiomerically pure polytungstates, Na-2[(CH3)(2)NH2](3){NaC{Ce-III(H2O)(CH3CH2OH)(L- tartH(3)) (H2Si2W19 O-66)}center dot 3.5 H2O (L-1) and [(CH3)(2)NH2](7){NaC[Ce-III(H2O)(CH3CH2OH)(D-tartH(3))(Si2W19O66)}center dot 2.5H(2)O (D-1), were successfully synthesized. Structural analysis indicates that chiral tartrate ligands directly connect with novel lacunary [Si2W19O66](10-) polytungstate units. Strong induced optical activity in the polyoxometalate (POM) units is manifested by circular dichroism spectroscopy. Z-scan analysis revealed that L-1 and D-1 are the first chiral POM-based complexes that exhibit two-photon absorption properties typical of the third-order nonlinear optical response.