Solid-liquid equilibria for six organic binary mixtures, namely, pentanedioic acid (1) + 3-methylheptanedioic acid (3) (eutectic temperature T-E = 329.94 K, eutectic composition x(1E) = 0.497); pentanedioic acid (1) + 2,2-dimethylbutanedioic acid (4) (T-E = 354.07 K, x(1E) = 0.740); pentanedioic acid (1) + 2,3-dimethylbutanedioic acid (5) (T-E = 338.95 K, x(1E) = 0.415); octanedioic acid (2) + 3-methylheptanedioic acid (3) (T-E = 352.54 K, x(1E) = 0.144); octanedioic acid (2) + 2,2-dimethylbutanedioic acid (4) (T-E = 386.49 K, x(1E) = 0.416); and octanedioic acid (2) + 2,3-dimethylbutanedioic acid (5) (T-E = 368.30 K, x(1E) = 0.193, are measured in this study using differential scanning calorimetry. Simple eutectic behaviors for these systems are observed. The experimental results are correlated using the Wilson and nonrandom two-liquid activity coefficient models, and satisfactory results are presented.