The control of chirality by optical molecular switches offers intrigui
ng prospects in the design of new materials. For example, photochemica
lly induced stilbene-type cis-trans isomerization of 1 (see Figure) re
sults simultaneously in reversal of the helicity. The molecular design
of switching units, the possibility of highly stereoselective optical
molecular switching, and an approach to a gated response are describe
d.