| abstract |
The present invention relates to benzo[f]chromene and pyrano[3,2-f]-chromene derivatives of the formula I n nin whichn nL 1 , L 2 , R 1 , R 2 , A 1 , A 2 , Z 1 , Z 2 , m and n are as defined in claim 1 , to the preparation thereof, to the use thereof as components in liquid-crystalline media, and to electro-optical display elements which contain the liquid-crystalline media according to the invention. |