Carborane acid was first discovered and synthesized by Professor Christopher Reed and his colleagues in 2004 at the University of California, Riverside. The parent molecule from which carborane acid is derived, an icosahedral carboranate anion, , was first synthesized at DuPont in 1967 by Walter Knoth. Research into this molecule's properties was put on hiatus until the mid 1980s when the Czech group of boron scientists, Plešek, Štíbr, and Heřmánek improved the process for halogenation of carborane molecules. These findings were instrumental in developing the current procedure for carborane acid synthesis. The process consists of treating Cs[HCBH] with , refluxing under dry argon to fully chlorinate the molecule yielding carborane acid, but this has been shown to fully chlorinate only under select conditions.
In 2010, Reed published a guide giving detailed procedures for the synthesis of carborane acids and their derivatives. Nevertheless, the synthesis of carborane acids remains lengthy and difficult and requires a well-maintained glovebox and some specialized equipment.  The starting material is commercially available decaborane(14), a highly toxic substance.  The most well-studied carborane acid  is prepared in 13 steps.  The last few steps are especially sensitive and require a glovebox at O without any weakly basic solvent vapors, since bases as weak as benzene or dichloromethane will react with carborane-based electrophiles and Brønsted acids.  The final step of the synthesis is the metathesis of the μ-hydridodisilylium carboranate salt with excess liquid, anhydrous hydrogen chloride, presumably driven by the formation of strong Si–Cl and H–H bonds in the volatile byproducts:
::[EtSi–H–SiEt][HCBCl] + 2HCl → + 2EtSiCl + H
The product was isolated by evaporation of the byproducts and was characterized by its infrared (ν = 3023 cm) and nuclear magnetic resonance (δ 4.55 (s, 1H, CH), 20.4 (s, 1H, H) in liquid SO) spectra (note the extremely downfield chemical shift of the acidic proton). Although the reactions used in the synthesis are analogous, obtaining a pure sample of the more acidic  turned out to be even more difficult, requiring extremely rigorous procedures to exclude traces of weakly basic impurities.