A stoichiometric reaction was used to investigate the interaction between crystal violet 1 and BH3. One equivalent of BH3 did not result in an immediate colour change, however the addition of two equivalents of BH3 resulted in a colourless solution alongside the precipitation of a pale blue solid (Scheme 2). Solution-state 1 H, C{ 1 H} and 11 B NMR spectroscopic analyses confirmed the structure of the bis(crystal violet-borane) adduct 2.