In summary, the 2D porous material with unique pore configuration, ultrathin structure, abundant mesopores and appealing surface properties, is one of the most promising candidates for obtaining efficient functional nanomaterials for the practical applications. The reported monolayer mesoporous nanosheets consisting of “U-shaped” mesopore units with a unique surface asymmetry can exhibit a high demulsification efficiency and stability. The formation mechanism and the structure-activity relationship of such 2D mesoporous Janus nanosheet were also revealed. Nevertheless, the component obtained by this dual-emulsion-directed monomicelle assembly was only for the organosilica, and it was hard to extend to other components, limiting their potential application. So, it is significant to improve the versatility of this synthetic strategy. Overall, the current work contributes new insights to the invention of the brand-new mesoporous materials with hierarchical structures, new pore configuration and surface properties, which can attract a broad readership in chemistry, materials science, and biomedical engineering.