Benzo f chromene and pyrano 3,2-f chromene derivatives

摘要

The present invention relates to benzo [f] chromene and pyrano [3,2-f] chromene derivatives of the formula I $ F1 wherein L1, L2, R1, R2, A1, A2, Z1, Z2, m and n are as in claim 1, their preparation, their use as components in liquid-crystalline media and electro-optical display elements containing the liquid-crystalline media according to the invention.