The reaction of terbium and europium salts with the lacunary polyxometalate (POM) [As2W19O67(H2O)](14-) and 2-picolinic acid (picH) affords the ternary lanthanoid-organic-polyoxometalate (Ln-org-POM) complexes [Tb-2(pic)(H2O)(2)(B-beta-AsW8O30)(2)(WO2(pic))(3)](10-) (1), (Tb-8(pic)(6)(H2O)(22)(B-beta-AsW8O30)(4)(WO2(pic))(6)](12-) (2), and [Eu-8(pic)(6)(H2O)(22)(B-beta-AsW8O30)(4)(WO2(pic))(6)](12-) (3). A detailed synthetic investigation has established the conditions required to isolate pure bulk samples of the three complexes as the mixed salts H0.5K8.5Na-[1]center dot 30H(2)O, K4Li4H4[2]center dot 58H(2)O, and Eu1.66K7[3]center dot 54H(2)O, each of which has been characterized by single crystal X-ray diffraction. Complexes 2 and 3 are isostructural and can be considered to be composed of two molecules of 1 linked through an inversion center with four additional picolinate-chelated lanthanoid centers. When irradiated with a laboratory UV lamp at room temperature, compounds K4Li4H4[2]center dot 58H(2)O and Eu1.66K7[3]center dot 54H(2)O visibly luminesce green and red, respectively, while compound H0.5K8.5Na[1]center dot 30H(2)O is not luminescent. A variable temperature photophysical investigation of the three compounds has revealed that both the organic picolinate ligands and the inorganic POM ligands sensitize the lanthanoid(III) luminescence, following excitation with UV light. However, considerably different temperature dependencies are observed for Tb(III) versus Eu(III) through the two distinct sensitization pathways.