The thermal properties for binary mixtures at various weight fraction ratios between dodecyl carbonate (1a), tetradecyl carbonate (1b), hexadecyl carbonate (1c), and octadecyl carbonate (1d) were examined by DSC at 0.5, 1.0, and 5.0°C/min. At 5°C/min sharp well defined phase transitions were observed at 80:20, 88:12, and 90:10, for 1a:(1b, 1c, and 1d), respectively, at 74:26 and 80:20 for 1b:(1c, and 1d), respectively, and at 82.5:17 for 1c:1d. The melting and solidification temperatures for these mixtures ranged between 12–37°C (melting) and 8–34°C (solidification). The latent heat of melting and solidification determined for the binary carbonate mixtures ranged between 135 and 175 J/g. At 0.5 or 1.0°C/min, mixtures of 1a:(1b, 1c, and 1d) and 1b:1d melted and solidified similarly when run at 5°C/min while the melting curves for 1b:1c and 1c:1d were not as well defined. These carbonate mixtures extend the thermal properties of the pure oleochemical carbonates and compliment other biobased phase change materials (PCMs) substances such as fatty acids, esters, and alcohols and may provide useful biobased alternatives to paraffin wax and salt hydrate PCM currently dominating the market.