(E)‐3‐(Benzo[b]thiophen‐2‐yl)‐2‐(3, 4, 5‐trimethoxyphenyl)acrylonitrile and (Z)‐3‐(benzo[b]thiophen‐2‐yl)‐2‐(3, 4‐dimethoxyphenyl)acrylonitrile. Corrigendum. (11th April 2013)