Cover Picture: Thermal and Photolytic Transformation of NHC–B, N‐Heterocycles: Controlled Generation of Blue Fluorescent 1, 3‐Azaborinine Derivatives and 1H‐Imidazo[1, 2‐a]indoles by External Stimuli (Chem. Eur. J. 40/2015). Issue 40 (16th September 2015)