A nonlinear optical crystal cadmium–ytterbium oxyborate Cd₄YbO(BO₃)₃ has been synthesized through high-temperature solid-state reactions. In the crystal structure, CdO_n (n = 6, 8), YbO₆ distorted polyhedra and π-delocalization BO₃ groups interconnect via shared edges and corners to form a complicated three-dimensional (3D) network. The second harmonic generation (SHG) measurement shows that Cd₄YbO(BO₃)₃ possesses a large SHG response about four times that of KH₂PO₄ (KDP) and is phase-matchable in the visible region. In addition, it exhibits a wide transparent region ranging from near UV to middle IR. The title compound melts congruently suggesting that this material is a promising NLO material.