A new two-dimensional framework germanate, Ge3O5(OH)(4)[C2N2H10] (denoted ICMM-8), with a 3:9 Ge:O ratio has been synthesized, using a mixture of pyridine, water, and ethanol as the solvent and 1,4-diazabicyclo[2.2.2]octane and ethylenediamine as the structure-directing agents, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction. In this new compound, the GeO2 natrolite-type infinite four and eight R-containing layers appears for the first time in a pure GeO2 framework. The total 2D structure is built up from SBU-6, four tetrahedra, and two octahedra. The hydroxyl groups occupy four positions of each octahedral germanium atom. The compound is characterized by IR spectra and TGA-DTA. Crystal data: Ge3O5(OH)(4)[C2N2H10], monoclinic space group P2(1)/c; a = 11.3570(9) angstrom, b = 8.8819(7) angstrom, c = 9.9200(8) angstrom, beta = 90.710(1), V = 1000.6(1) angstrom(3), Z = 4, R-1 = 0.044 (l > 2(l)), and wR(2) = 0.1051 (all data).