Multiple bonds between boron and transition metals are known in many borylene (:BR) complexes via metal dπ→BR back‐donation, despite the electron deficiency of boron. An electron‐precise metal–boron triple bond was first observed in BiB2O− Bi≡B−B≡O− in which both boron atoms can be viewed as sp‐hybridized and the B−BO− fragment is isoelectronic to a carbyne (CR). To search for the first electron‐precise transition‐metal‐boron triple‐bond species, we have produced IrB2O− and ReB2O− and investigated them by photoelectron spectroscopy and quantum‐chemical calculations. The results allow to elucidate the structures and bonding in the two clusters. We find IrB2O− has a closed‐shell bent structure (Cs, 1A′) with BO− coordinated to an Ir≡B unit, (−OB)Ir≡B, whereas ReB2O− is linear (C∞v, 3Σ−) with an electron‐precise Re≡B triple bond, Re≡B−B≡O−. The results suggest the intriguing possibility of synthesizing compounds with electron‐precise M≡B triple bonds analogous to classical carbyne systems. To bend or not to bend: Photoelectron spectroscopy and ab‐initio calculations show that IrB2O− has a bent (−OB)Ir≡B structure and ReB2O− has a linear structure, Re≡B−B≡O−. The latter is the first example of a transition‐metal borylyne complex.