Two new isostructural rare-earth oxyborates ScMO(BO3) (M = Ca and Cd) with a three-dimensional (3D) cationic framework and parallel arranged [BO3] triangles have been synthesized by the flux method. In the 3D cationic framework, an interesting sandwich-like basic building unit (BBU) is constructed by two 1(infinity)[Ca(1) O-4](6-) chains and two 1(infinity)[Sc(1) O-4](5-) chains. ScMO(BO3) melt incongruently, which shows that title compounds can be grown by the flux method. The UV cut-off edges for ScCaO(BO3) and ScCdO(BO3) are 230 and 249 nm, respectively. In addition, the first-principles calculations are performed to gain further insights into the relationship between the microscopic electronic structures and associated optical properties