Theoretical　calculations　are　performed　to　probe　the　geometric　and　electronic　properties　of　diniobium　boride　clusters,　Nb2Bx　–/0　(x　=　1–6).　Generalized　Koopmans＇　theorem　is　utilized　to　predict　vertical　detachment　energies　(VDEs)　and　to　simulate　the　photoelectron　spectra　(PES).　Density　functional　theory　(DFT)　calculations　are　carried　out　at　the　BP86　level　to　hunt　for　the　most　stable　structures　of　the　abovementioned　species.　A　fascinating　structural　evolution　is　observed　in　Nb2Bx　–　(x　=　1–6)　clusters,　which　shows　the　equatorial　boron　chain　extending　around　the　Nb–Nb　dimer,　with　increasing　x,　and　an　enclosed　planar　B6　ring　emerges　in　the　Nb2B6　–　species.　Moreover,　the　neutral　species　Nb2Bx　(x　=　1–6)　shares　a　similar　structural　evolution　with　the　anionic　species.　The　B6　molecular　ring　in　bipyramidal　Nb2B6　–/0　species　is　a　promising　building　block,　which　may　be　expected　to　provide　significant　insights　into　the　design　of　new　borometallic　complexes.　©　2018　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim