DDiKTa-A was obtained in one step from DiKTa-Br 29 via a two-fold palladium-catalysed Buchwald-Hartwig cross-coupling reaction with 4-tert-butylaniline (Scheme S1). DDiKTa-A was purified by column chromatography and then by gradient-temperature vacuum sublimation. The identity and purity of DDiKTa-A was assessed using a combination of 1 H & 13 C nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, melting point determination, highpressure liquid chromatography and elemental analysis (Figures ).