Synthesis, stability and bonding situation of tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cationsElectronic supplementary information (ESI) available: CV waves of compounds 7a, 8a and 9a, redox details of compounds 7a,b, 8a,b, and 9a,b along with those of 4a, 5a and 6a, ORTEP drawings and details of the X-ray analyses of compounds 2b and 9b and NMR details of the compounds reported. See http://www.rsc.org/suppdata/ob/b3/b302688d/