Volatile organic solvents were considered to have little influence on the synthesis of mesostructured materials through evaporation-induced self-assembly(EISA),because upon evaporation they leave the sol and hence do not interfere with the self-assembly process.We show here that the choice of solvent is crucial in the synthesis of thin films of phenylene-bridged periodic mesoporous organosilica(benzene PMO).Methanol is found to be a better solvent for the synthesis of thin films,whereas ethanol favors the formation of(HO)3Si-C6H4-Si(OH)3 crystals,the identity and structure of which is established by X-ray diffraction.A ternary reactant composition diagram is designed to visualize the relationship among multiple synthesis experiments and to guide the interpretation of experimental results and optimization of the quality of the periodic mesoporous organosilica film.Our study highlights the importance of solvent choice,a factor often neglected in EISA.We expect it to inspire researchers to explore the effect of solvent in designing the synthesis of mesoporous materials. Volatile organic solvents were considered to have little influence on the synthesis of mesostructured materials through evaporation-induced self-assembly (EISA), because upon evaporation they leave the sol and hence do not interfere with the self-assembly process. We show here that the choice of solvent is crucial in the synthesis of thin films of phenylene-bridged periodic mesoporous organosilica (benzene PMO). Methanol is found to be a better solvent for the synthesis of thin films, of ethanol favors the formation of (HO) 3Si-C6H4 -Si (OH) 3 crystals, the identity and structure of which is established by X-ray diffraction. An aromatic reactant composition diagram is designed to visualize the relationship among multiple synthesis experiments and to guide the interpretation of experimental results and optimization of the quality of the periodic mesoporous organosilica film. Our study highlights the importance of solvent choice, a factor often neglected in EISA.We expect it to inspire researchers t o explore the effect of solvent in designing the synthesis of mesoporous materials.