The solid-liquid phase behavior has been measured for the binary systems (C6H6 + n-C14H30), (C6H6 + n-C16H34), (C6H12 + n-C14H30), and (C6H12 + n-C16H34) at temperatures from 230 to 323 K and pressures up to 120 MPa by the visual observation of the phase transition using a high-pressure optical vessel with the aid of a video microscope. The uncertainties in measurements of temperature, pressure, and composition are within 0.1 K, 0.5 MPa and 0.001 mole fraction, respectively. The solid-liquid equilibrium (SLE) diagrams of the investigated systems consist of two liquidus curves intersecting at the eutectic point. Two components in each system have immiscibility in the solid phase, while they are completely miscible in the liquid phase. The solid-liquid coexistence curve and the eutectic point are found to increase to higher temperatures monotonically with increasing pressure in each system. The SLE diagrams at atmospheric pressure could be predicted successfully by the UNIFAC estimation method.