Unlike carbon, boron does not usually form ring compounds due to its electron deficiencydriven affinity towards polyhedral geometries.1-3 Therefore, the planar boron rings were ignored for a long time. However, recent developments by us and others demand further attention in stabilizing planar boron rings. For example, Himmel and co-workers synthesized a derivative of a doubly base-stabilized [B3H6] +, the structural equivalent of [B3H8] - and [B3H9].4a Although the smaller B3 and B4-rings are mostly isolated as individual species, larger B5 and B6-rings are stabilized by TMs, depending on the ring size and electronic requirements of the rings.1,4 In this regard, we have recently synthesized and structurally characterized tetraborane ring [B4H8] 2- and pentaborane ring [B5H10] - stabilized by Os-template in ɳ4 or ɳ5 -fashion which mimics [C4H4] 2- and [C5H5] - rings, respectively.4c We have also isolated the first examples of a nearly planar [B6H6] unit, stabilized as a part of [(Cp*Ti)2(μ-ɳ6 :ɳ6 -B6H6)(μ-H)6], where significant electron delocalization was observed from the Ti–Ti bonding orbital to the μ-H atoms and B6 skeleton.4d The selection of transition metals mostly depends on their diffuse orbitals, valence electrons, and ring sizes, while the bridging hydrogens balanced the electron deficiency of the borane rings. These results will be discussed in detail.