Tailoring functionalized nanostructures at the atomic scale is of importance in nanotechnology. We report on the controllable fabrication of linear polyphenyl wires by direct C–H activation and C–C coupling of para-sexiphenyl (p-6P) on an anisotropic Au(110) surface. Because of the one-dimensional spatial constraint at the surface, the equivalent C–H bonds of p-6P molecules were differentiated with various reaction probabilities. Consequently, linear polymerization of p-6P was achieved via C–C bonding at the meta-sites, with the kink formation every 6 phenylene units. On the other hand, branched polymerization was efficiently suppressed. Among such kinked polyphenyl wires, the trans conformation is predominant, compared with the cis conformation. Furthermore, exclusive C–C bond formation at the p-6P para-sites has been promoted by the neighboring terphenyl radicals, which possess reactive para-sites, resulting in the formation of straight para-polyphenyl wires instead of kinked ones. Our study demonstrate...