Room temperature photochromic liquid crystal [3H]-naphtho[2,1-b]pyrans-photochromism in the mesomorphic state.

Photochromic liquid crystals based on [2H]-chromenes functionalised in the 3,3[prime or minute]-positions by phenyl groups linked to 4-cyano-4[prime or minute]-hydroxybiphenyl groups via alkyl and siloxane spacers as chromophore were synthesised and the photochromic and mesomorphic behaviour was investigated. Copyright 2004 The Royal Society of Chemistry