Boron and mixed-boron clusters have received considerable attention because of their wide applications and their essential roles in advancing chemical bonding models. Bearing the bright prospects as building blocks to form novel polymeric materials, the sulfur-rich boron sulfides have been greatly studied. However, the knowledge of the boron-rich boron sulfides is much rare. In this article, we report an extensive theoretical study on the structural, energetic, and stability features of a hitherto unknown septa-atomic cluster B 6 S at the CCSD(T)/6-311þG(2df)//B3LYP/6-311þG(d) level. The local minimum isomers were obtained through our recently developed program ''grid-based comprehensive isomeric search algorithm.'' The results show that the planar knife-like isomer B 5 (ÀBS) 01 (0.0 kcal/mol) containing the ÀBS moiety is the lowest energy, followed by the quasi-planar belt-like isomer B 6 (>S) 02 (6.7 kcal/mol) and the pyramid-like isomer B 6 (>S) 03 (8.4 kcal/mol). Notably, the three singlet isomers all have good kinetic stability on the basis of the potential energy surface analysis. The B/S-centered wheel-like isomers are unfavorable in thermodynamics and kinetics. The triplet state structures generally can not compete with the singlet ones. The results are compared to the analogous and isoelectronic cluster B 6 O. Our work is expected to provide useful information for understanding the Correspondence