Five new vanadium selenites, Ca-2(VO2)(2)(SeO3)(3)(H2O)(2), Sr-2(VO2)(2)(SeO3)(3), Ba(V2O5)(SeO3), Sr-4(VO2)(2)(SeO3)(4)(Se2O5), and Pb-4(VO2)(2)(SeO3)(4)(Se2O5), have been synthesized and characterized. Their crystal structures were determined by single crystal X-ray diffraction. The compounds exhibit one- or two-dimensional structures consisting of corner- and edge-shared VO4, VO5, VO6, and SeO3 polyhedra. Of the reported materials, A(4)(VO2)(2)(SeO3)(4)(Se2O5) (A = Sr2+ or Pb2+) are noncentrosymmetric (NCS) and polar. Powder second-harmonic generation (SHG) measurements revealed SHG efficiencies of approximately 130 and 150 X alpha-SiO2 for Sr-4(VO2)(2)(SeO3)(4)(Se2O5) and Pb-4(VO2)(2)(SeO3)(4)(Se2O5), respectively. Piezoelectric charge constants of 43 and 53 pm/V, and pyroelectric coefficients of -27 and -42 mu C/m(2.)K at obtained for Sr4(VO2)(2)(SeO3)(4)(Se2O5) and Pb-4(VO2)(2)(SeO3)(4)(Se2O5), respectively. Frequency dependent polarization measurements confirmed that the materials are not ferroelectric, that is, the observed polarization cannot be reversed. In addition, the lone-pair on the Se4+ cation may be considered as stereo-active consistent with calculations. For all of the reported materials, infrared, UV-vis, thermogravimetric, and differential thermal analysis measurements were performed. Crystal data: Ca-2(VO2)(2)(SeO3)(3)(H2O)(2), orthorhombic, space group Pnma (No. 62), a = 7.827(4) angstrom, b = 16.764(5) angstrom, c = 9.679(5) angstrom, V = 1270.1(9) angstrom(3), and Z = 4; Sr-2(VO2)(2)(SeO3)(3), monoclinic, space group P2(1)/c (No. 12), a = 14.739(13) angstrom, b = 9.788(8) angstrom, c = 8.440(7) angstrom, beta = 96.881(11)degrees, V = 1208.8(18) angstrom(3), and Z = 4; Ba(V2O5)(SeO3), orthorhombic, space group Pnma (No. 62), a = 13.9287(7) angstrom, b = 5.3787(3) angstrom, c = 8.9853(5) angstrom, V = 673.16(6) angstrom(3), and Z = 4; Sr-4(VO2)(2)(SeO3)(4)(Se2O5), orthorhombic, space group Fdd2 (No. 43), a = 25.161(3) angstrom, b = 12.1579(15) angstrom, c = 12.8592(16) angstrom, V= 3933.7(8) angstrom(3), and Z = 8; Pb-4(VO2)(2)-(SeO3)(4)(Se2O5), orthorhombic, space group Fdd2 (No. 43), a = 25.029(2) angstrom, b = 12.2147(10) angstrom, c = 13.0154(10) angstrom, V= 3979.1(6) angstrom 3, and Z = 8.