As advanced in the beginning of this article, on Au(110) the situation is completely different. As occurs on Au(111), the initial reactions are dominated by Ullmann coupling. However, the action of the highly anisotropic Au(110) surface as a template limits the reaction products to structures composed of collinear reactant molecules, which in turn limits the possible Ullmann coupling products to d2 and d3. Out of these two structures d3 is much less common. Henceforth we will thus only focus on structures hierarchically built from d2. To covalently couple d2 molecules the methyl groups need first to be activated through the formation of the corresponding benzylic radicals. This requires higher temperatures than the Ullmann coupling, namely in the order of 525 K. Whereas on Au(111) such temperature treatment results in highly disordered polymers (Figure ), the uniaxial monomer alignment on Au(110) drives a polymerization of d2 molecules into regular non-benzenoid one-dimensional polymers (Figure ).