Two compounds (AH(2))(0.5)V2O5 (A = ethylenediamine, piperazine) have been synthesized hydrothermally (180 degrees C, 24 h, autogeneous pressure). They are triclinic (space group ) with the following parameters : a = 6.253(3) Angstrom, b = 6.397(4) Angstrom, c = 7.470(4) Angstrom, alpha = 78.67(4)degrees, beta = 80.16(4)degrees, gamma = 77.20(4)degrees with Z = 2 for A = ethylenediamine; a = 6.3913(7) Angstrom, b = 6.4151(8) Angstrom, c = 8.2041(9) Angstrom, alpha = 94.508(7)degrees, beta = 105.934(7)degrees, gamma = 104.030(5)degrees with Z = 2 for A = piperazine. The inorganic layer are formulated [V2O5](-) with V-IV and V-V located on two different crystallographic sites. Vanadium(IV) realizes a square pyramidal coordination. Each (VO5)-O-IV polyhedron shares an edge with another one to ensure [V2O8] units in which the two terminal apices point respectively up and down relative to the middle plane constituted by the six equatorial oxygens. Vanadium(V) is tetrahedrally coordinated; each (VO4)-O-V tetrahedron is linked to three [V2O8] units, the fourth oxygen being free.