The solution-mediated syntheses and single-crystal structures of (CN3H6)(2) . Zn-3(HPO3)(4) . H2O (I) an H3N(CH2)(3)NH3 . Zn-3(HPO3)(4) . H2O (II) are reported. These phases contain networks of vertex-sharing ZnO4 tetrahedra and HPO3 pseudopyramids accompanied by organic cations and water molecules. Despite their similar formulae, these phases adopt different crystal structures, in terms of three-dimensional and two-dimensional ZnO4\HPO3 networks, for I and II, respectively. Their similarities and differences to other zinc phosphites and phosphates are briefly discussed. Crystal data: (CN3H6)(2) . Zn-3(HPO3)(4) . H2O, M-r = 654.23, triclinic, P (1) over bar (No. 2), a = 7.5121 (3) Angstrom, b = 8.9927 (4) Angstrom, c = 15.1530 (6) Angstrom, alpha = 90.256 (1)degrees, beta = 93.391 (1)degrees, gamma = 111.091 (1)degrees, V = 953.04 (7) Angstrom(3) Z = 2, R(F) = 0.048, wR(F-2) = 0.121. H3N(CH2)(3)NH3 . Zn-3(HPO3)(4) . H2O, M-r = 610.22, monoclinic, C2/c (No. 15), a = 8.9310 (4) Angstrom b = 14.4308 (6) Angstrom, c = 14.3669 (6) Angstrom, beta = 104.624 (1)degrees, V = 1791.64 (13) Angstrom(3), Z = 4, R(F) = 0.033, wR(F-2) = 0.087. (C) 2002 Elsevier Science (USA).