Benzochromene derivatives

A compound of formula I

• wherein
• Y is —CO—, —CS—, —CH2—, —CF2— or —CHF—,
• L1 and L2 are each, independently of one another, H, F, Cl or —CN,
• are each, independently of one another, and, if present more than once, also independently of one another,
• (a) a trans-1,4-cyclohexylene radical, in which, one or two non-adjacent CH2 groups are optionally replaced by —O— and/or —S—,
• (b) a 1,4-cyclohexenylene radical,
• (c) a 1,4-phenylene radical, in which, one or two non-adjacent CH groups are optionally replaced by N, or
• (d) 1,4-bicyclo[2.2.2]octylene, 1,3-bicyclo[1.1.1]pentylene, spiro[3.3]heptane-2,4-diyl, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl,
• R1 and R2 are each, independently of one another, H, halogen, —CN, —SCN, —SF5, —CF3, —CHF2, —CH2F, —OCF3, —OCHF2, or an alkyl group having 1 to 15 carbon atoms which is monosubstituted by CN or CF3 or at least monosubstituted by halogen, and in which one or more CH2 groups each, independently of one another, are optionally replaced by —O—, —S—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—,
• —CO—, —CO—O—, —O—CO— or —O—CO—O— in such a way that neither O nor S atoms are linked directly to one another,
• Z1 and Z2 are each, independently of one another, —CH2—CH2—, —CF2—CF2—, —CF2—CH2—, —CH2—CF2—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —C═C—, —COO—, —OCO—, —CH2O—, —OCH2—, —CF2O—, or —OCF2—, or a combination of two of these groups, where no two O atoms are bonded to one another, and
• n and m are each 0, 1 or 2, where
• n+m is 0, 1, 2 or 3,
• with the proviso that, if Y is —CO—, at least one of L1 and L2 is not H.