CA4 and cancer: In continuation of our work on the development of benzo­thio­phene cyano combretastatin A-4 analogs as anti-cancer agents (Penthala et al., 2013 ▶), we have synthesized a series of novel CA-4 analogs by constructing a triazole ring structure (I) by chemical modification of the cyano group on the stilbene unit of cyano-CA-4 analogs utilizing a [3 + 2]cyclo­addition azide condensation reaction with sodium azide in the presence of l-proline Lewis base as catalyst.