The geometries, stabilities, and electronic properties of Sc 2 B n clusters, up to n=10, have been systematically investigated by using the density-functional B3LYP and CCSD(T) method. It was found that the ground state structures of the B n clusters are substantially modified by the doping of Sc atoms. Sc 2 B n clusters have very regular growth pattern, namely to form bipyramid. All the most stable Sc 2 B n can be viewed as bipyramid (uncompleted when n⩽5) with two Sc atoms at the apexes. Sc 2 B 7 and Sc 2 B 8 are confirmed as the magic number clusters based on the analysis of the second-order difference of energies. The dissociation energies, vertical ionization potentials (VIP) and electron affinities (VEA) of Sc 2 B n isomers are discussed. In most of the case, the Sc 2 B n clusters have smaller HOMO–LUMO gap, VIP, VEA than the corresponding B n clusters. There was no explicit correlation between the energetic stability and HOMO–LUMO gap, VIP or VEA.