We investigate the influence of temperature on the self-assembly of 2,6,11-tricarboxydecyloxy-3,7,10-triundecyloxy triphenylene (asym-TTT) adsorbed on HOPG using scanning tunneling microscopy (STM) at the liquid/solid interface. We show that the packing structures of 2D self-assembled asym-TTT can be precisely tuned by adjusting the substrate temperature. The temperature change from 20 °C to 35 °C induces two phase transitions and increment in the packing density from 0.161 to 0.179 molecules per nm(2). The density-functional theory (DFT) calculations reveal that their interaction energies are similar. In particular, the experimental findings further illustrate the preferential adsorption of guest molecules, such as phthalocyanine, only in the domain of more close packing structures.