Mesoporous graphene (MG) was successfully synthesized by using the soft-template method with graphite oxide (GO) and triblock co-polymer (P123). The obtained MGs exhibit a high surface area as well as tuned pore parameters by preparing GO/P123 composite gel under different reaction conditions. Freeze-drying of the composite gel leads to physical interaction between the GO sheets, which induced the largest pores in MG. While, hydrothermal treatment can generate the chemical linkage between GOs through various reactions of oxygen functional groups on GOs, it facilitates the formation of relatively smaller and more uniform pores. Especially, the presence of a base catalyst under hydrothermal reaction accelerates the chemical reactions, which causes the smallest and most uniform pores. As controlling the interaction between GOs, the pore size of the MGs was easily fine-tuned in a few nanometer-scales never reported. Herein, the electrochemical performance was preliminarily tested as a supercapacitor among the various applications of MG. As a results, the hydrothermal treated sample shows the highest specific capacitance of 151.8 Fg(-1) at a current density of 0.1 Ag-1 .Additionally, it exhibits excellent cycle stability with similar to 96% retention of its initial capacitance at a current density of 3.0 Ag-1 even after 5000 cycles. (C) 2018 Elsevier Ltd. All rights reserved.