B-doped single-walled carbon nanotubes have been synthesized from sodium tetraphenyl borate and record incorporation percentages of B heteroatoms have been found in this material as-synthesized. However, carbonaceous impurities, besides other byproducts, can still contain boron and therefore exhibit various types of competing bonding environments. To circumvent this issue, which has constantly hindered a conclusive insight to the existing bonding environments in materials alike, we have employed a purification method, which leaves ∼7% at. of B atoms of the total sample composition almost exclusively in the sp2 configuration. This record B substitutional doping, together with the identification of the competing bonding environments are revealed here unambiguously from X-ray photoelectron spectroscopy. The doping level in the purified tubes is about an order of magnitude larger than in other B-doped single-walled tubes even without purification, and brings the state-of-the-art closer to the controlled applicability of this material.