The invention relates to chiral compounds of formula (I) wherein Y1, Y2, Y3, Y4, X1, X2, X3 and X4 have the meaning given in claim 1, to liquid crystalline mixtures comprising at least one chiral compound of formula (I), to chiral linear or crosslinked liquid crystalline polymers obtainable by polymerizing a polymerizable mixture comprising at least one chiral compound of formula (I) to the use of chiral compounds of formula (I) and mixtures and polymers obtained thereof in liquid crystal displays, active and passive optical elements, adhesives, synthetic resins with anisotropic mechanical properties, cosmetic and pharmaceutical compostions, diagnostics, liquid crystal pigments, for decorative and security applications, nonlinear optics, optical information storage or as chiral dopants, and to a liquid crystal display comprising a mixture comprising at least one chiral compound of formula (I). 1