Diastereoselective, synergistic dual-mode optical switch with integrated chirochromic helicene and photochromic bis-azobenzene moieties.

An unprecedented dual-mode optical switch by combining helicene and bis-azobenzene moieties in proximity allows for cooperative, highly diastereoselective chirochromic (92/8 to 3/97) and photochromic (>99/<1 to 19/81) switchings both in solution and in nematic LC with tunable pitches and handedness by permutation of four different metastable states.