Two new three-dimensional open-framework cobalt phosphates, [C2N2H10](2)[Co-4(PO4)(4)]H2O. It and [C4N3H16](3)- [Co-6(PO4)(5)(HPO4)(3)]H2O, II, have been prepared by the reaction of amine phosphates with Co2+ salts. X could also be prepared by the reaction of the cobalt tris amine complex with H3PO4 The crystal data for X and II are as follows: phosphate I, orthorhombic, space group P2(1)2(1)2(1) (no. 19), a = 10.277 (L) Angstrom, b = 10.302 (1) Angstrom, c = 18.836 (1) Angstrom, V = 1994,2 (2) Angstrom(3), Z = 4; phosphate II, monoclinic, space group P2(1)/c (No. 14), a = 31.950 (1) Angstrom, b = 8.360 (1) Angstrom, c = 15.920 (1) Angstrom, beta = 96.6 (1)degrees V = 4223.4 (2) Angstrom(3), Z = 4. The structures of both X and II are constructed from alternating CoO4 and PO4 tetrahedra. The connectivity leads to the formation of eight-membered channels in all the crystallographic directions resembling the aluminosilicate zeolite, merlinoite in the case of I and to a rather large, one-dimensional 16-membered channel in IT. Strong hydrogen-bond interactions involving the amine and framework oxygens are present in both I and II.