The precise control of molecular self-assembly on surfaces presents many opportunities for the creation of complex nanostructures. Within this endeavor, selective patterning by exploiting molecular interactions at the solid-liquid interface would be a beneficial capability. Using scanning tunneling microscopy at the 1,2,4-trichlorobenzene/Au(111) interface, we observed selective self-assembly of 1,3,5-tris(4-methoxyphenyl)benzene (TMPB) molecules in the face-centered cubic (FCC) regions of Au(111). Density functional theory calculations suggest higher adsorption energy of TMPB molecules at FCC regions, explaining the preference for self-assembly. The molecular coverage is found to increase with the concentration of the applied solution, eventually yielding a full monolayer. Moreover, the adsorption of TMPB molecules induces a concentration-dependent lifting of the herringbone reconstruction, observed as an increase in the area of the FCC regions at higher concentrations. Our results represent a simple and cost-effective selective nanoscale patterning method on Au(111), providing a possible avenue to guide the co-adsorption of other functional molecules.