All reactions were carried out under argon atmosphere. Solvents were dried by the usual methods and then distilled prior to use. Sublimation was performed in a cylinder round-bottom flask equipped with a magnetic bar. NMR spectra were obtained at 300 MHz for 1 H NMR and at 75 MHz for 13 C NMR with chemical shift values in the spectra being referenced to the solvent. Elemental analyses were carried out with a Perkin-Elmer CHN analyser (2400 series II). Scheme S1. Four step synthesis of 2-methyl-5-nitrobenzo[b]thiophene (3).