Magic blue (MB+• SbCl6− salt), i.e. tris-4-bromophenylamminium cation radical, is a routinely employed one-electron oxidant that slowly decomposes in solid state upon storage to form so called ‘blues brothers’, which often complicate the quantitative analyses of the oxidation processes. Herein, we disclose the identity of main ‘blues brother’ as the cation radical and dication of tetrakis-(4-bromophenyl)benzidine (TAB) by a combined DFT and experimental approach, including isolation of TAB+• SbCl6− and its X-ray crystallography characterization. The formation of TAB in aged magic blue samples occurs by a Scholl-type coupling of a pair of MB followed by a loss of molecular bromine. This recognition led us to rational design and synthesis of tris(2-bromo-4-tert-butylphenyl)amine, referred to as ‘blues cousin’, (BC: Eox1 = 0.78 V vs Fc/Fc+, λmax(BC+•) = 805 nm, εmax = 9930 cm−1 M−1), whose oxidative dimerization is significantly hampered by positioning the sterically demanding tert-butyl groups at the para-positions of aryl rings. A ready two-step synthesis of BC from triphenylamine and the high stability of its cation radical (BC+•) promises that BC will serve as a ready replacement for MB and oxidant of choice for mechanistic investigations of one-electron transfer processes in organic, inorganic, and organometallic transformations.