Optically active biphenyl derivatives including optically active biphenyl carboxylic acid derivative, hydroxybiphenyl derivative, alkoxybiphenylalkanol derivative and alkoxybiphenylalkanol derivative have the following structural formula: ##STR1## wherein R.sup.1 represents an alkyl group of 3-20 carbon atoms, R.sup.2 represents an alkyl group or alkoxyalkyl group of 1-20 carbon atoms which may optionally be substituted with at least one halogen atom. X represents --O--, --COO-- or --OCO--, m represents 0 or 1, n represents an integer of 1-6 and p represents 0 or 1, and the * mark represents an asymmetric carbon atom. These optically active biphenyl derivatives are useful as a ferroelectric liquid crystal material or its component having a sufficient spontaneous polarization and by which a high speed response is possible and which further exhibits a ferroelectric liquid crystal phase in a temperature region around room temperature.