Ag2B4O7 is synthesized at high-pressure/high-temperature conditions of 11 GPa and 1073 K in a multianvil device. It crystallizes in the monoclinic centrosymmetric space group P21/c (no. 14) with four formula units per unit cell (Z=4). The cell parameters are a=787.53(3), b=651.63(2), c=943.88(3) pm, β=107.911(2)°, and V=460.90(3) Å3. Ag2B4O7 crystallizes in a unique crystal structure that consists of complex anionic borate layers with Ag+ ions in between. Additionally, the silver cations show argentophilic interactions. The compound was analysed via single-crystal and powder diffraction as well as infrared spectroscopy. Furthermore, theoretical calculations at HSEsol level were conducted.