A new acentric borate La₂Al_4.68B₈O₂₂ crystal was synthesized by a solid state reaction and the single crystals were successfully grown with B₂O₃–LiF flux using the top-seeded solution growth method. The structure of the titled crystal features a two-dimensional layered structure composed of [BO₄] and [AlO₅] groups that are bridged by the skeletal structure of the [LaO₆] polyhedron along the c axis. Optical properties including the transmittance spectrum, IR spectrum and refractive indices have been systematically evaluated for the first time.