In this study, erythritol tetra myristate and erythritol tetra laurate, as novel phase change materials (PCM) for latent heat thermal energy storage, were synthesized by the direct esterification reaction of the erythritol with myristic and lauric acids. The esterification reactions were proven by using Fourier transform infrared and nuclear magnetic resonance (H-1 NMR) spectroscopy techniques. The melting and freezing temperatures and latent heats of the esters were measured using differential scanning calorimetry analysis. The melting temperatures and latent heats of the erythritol tetra myristate and erythritol tetra laurate esters were determined as 10.82 and -9.03 degrees C and 180.90 and 161.39 J/g, respectively. The thermal cycling test indicated that the synthesized esters had good thermal reliability in terms of the changes in thermal properties after 1,000 thermal cycling. Thermal stability of the PCM was also investigated by using thermal gravimetric analysis. Moreover, the thermal conductivities of the synthesized esters were increased by about 28% for erythritol tetra myristate and 25% for erythritol tetra laurate by addition of 5 wt% expanded graphite. Based on all these results, it can be concluded that the synthesized esters as novel solid-liquid PCM have great potential for low temperature applications, such as transport of blood, operating tables, hot-cold therapies, and refrigerators.