Eutectic binary, ternary, and quaternary mixtures of the enantiotropic cyano and nitro derivatives of the two series, 4-hexadecyloxyphenyI-4'-substituted benzoates (I-a,I-b) and 4-substituted phenyl-4'-hexadecyloxy benzoates (IIa,b) in presence and in absence of the monotropic methoxy derivative (IIc) were prepared and their crystal-mesophase transition temperatures (T-E) were determined by DSC and identified with polarised-light microscopy. For mixtures of enantiotropes, the values of T-E obtained were found to be successfully correlated, by the Schroeder-van Laar equation, to the mole fraction chi(i), of each individual component. In each case of mixture containing the monotrope IIc, as one component, very poor correlation was observed.