A new manganese(II)-substituted aluminophosphate, [C6N2H14]0.5-[MnAl3(PO4)(4)(H2O)(2)], denoted as MnAPO-14, has been synthesized hydrothermally in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as the structure-directing agent. Its structure is determined by single-crystal X-ray diffraction analysis and further characterized by X-ray powder diffraction, ICP, and TG analyses. The structure of MnAPO-14 is built up by MnO4(H2O)(2) octahedra, AlO4 tetrahedra, and PO4 tetrahedra via Al-O-P and Mn-O-P linkages. Its framework is analogous to that of aluminophosphate zeotype AFN in which 25% of the aluminum sites are replaced by Mn(II) atoms. The diprotonated DABCO cations reside in the eight-membered ring channels. Computational simulations indicate that the substitution site of Mn to Al is determined by the host-guest interaction. Crystal data: [C6N2H14]0.5.[MnAl3(PO4)(4)(H2O)(2)], triclinic P (1) over bar (No. 2), a = 9.5121(4) Angstrom, b = 9.8819(3) Angstrom, c = 12.1172(4) Angstrom, alpha = 70.533(2)degrees, beta = 73.473(2)degrees, gamma = 82.328-(2)degrees, Z = 2, R-1 = 0.0586 (I > 2sigma(/)), and wR(2) = 0.1877 (all data).