Three new vanadyl gallium phosphates, (H(2)dap)(3)[(VO)(2)(GaO)(2)(PO4)(4)]center dot H2O (1), (H(2)dap)(1 5)[(VO)(2)(GaO)(2)(PO4)(3)]center dot 3H(2)O (2), and (H(2)dap)[(VO)(2)Ga-4(PO4)(6)(H2O)(4)]center dot 2H(2)O (3) (dap = 1,3-diaminopropane), have been prepared under mild solvothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, magnetic susceptibility, and EPR spectroscopy. They are the first examples of an organic/V4+/Ga/P/O system that displays three different dimensional structures with a common template. The 1 D chain structure of 1 and the 2D layered 2 are both built up with a PO4 and {V2Ga2O14} cluster which contains a syn-square pyramidal {V2O8} dimer and two GaO4 tetrahedra. The tetrameric cluster and V-O-Ga therein are observed in a metal phosphate system. Compound 3 is composed of VO5(H2O) octahedra, GaO4(H2O) trigonal bipyramids, and GaO4 and PO4 tetrahedra from which a unique 3D structure containing one-dimensional 12-ring channels is constructed. The channel aperture uncommonly comprises heterometal (V, Ga) polyhedra. Magnetic susceptibility data for 1-3 are consistent with V4+ and show a T-N of 12 K for 3. The unusual syn-{V2O8} dimers in 1 and 2 induce superexchange interactions, while isolated VO5(H2O) octahedra in 3 display super-super-exchange interaction. Electron paramagnetic resonance spectra with V-51 hyperfine structures were distinctly observed at 300 K for 1, while they started emerging at 30 K for 2 and 7 K for 3. The average hyperfine constant, 85 56 Gauss, was obtained via spectral simulations and nonlinear least-squares fittings for 1 and 2. Crystal data for 1 are triclinic, P (1) over bar, a = 9.1754(4) angstrom, b = 10 7853(5) angstrom, c = 15.6519(7) angstrom, alpha = 93.251 (1)degrees, beta = 92.530(1)degrees, gamma = 95 106(1)degrees, V = 1538.4(1) angstrom(3), and Z = 2; for 2, monoclinic, P2(1)/n, a = 8.9195(3) angstrom, b = 14 6374(5) angstrom, c = 17.8608(6) angstrom, beta = 97.272(1)degrees, V = 2313.1(1) angstrom(3), and Z = 4; and for 3, monoclinic, P2(1)/c, a = 9.0970(5) angstrom, b = 16.9940(9) angstrom, c = 9.6441(5) angstrom, beta = 103.456(3)degrees, V = 1450.0(1) angstrom(3), and Z = 4.