The phase behavior of binary mixtures of 4`-ethoxybenzylidene-4-n-butylaniline(EBBA) and 4-(nbutyl)-trans-cyclohexane carboxylic acid cyanophenol ester was investigated by determining the transition temperatures of crystal to mesophase and mesophase to isotropic phase and by observing the optical textures of liquid crystalline phases. In the textures of pure compounds, all exhibited well-developed nematic phases having Schlieren patterns and the eutactic behavior of transition from crystal to nematic phase. The mixtures of azoxy group (p-azoxyanisole) and Schiff-base material(EBBA) have a simple eutectic behavior, while the mixtures of EBBA and ester showed mixed polymorphism near the eutectic compositions, including smectic, a fan-shaped texture, and nematic at 25-43 mole%.