Plasmonic nanoparticles (NPs) have been the subject of extensive research, due to their remarkable optical properties. These properties arise from a collective oscillation of the conductive electrons at the NP surface, under light irradiation. This chapter demonstrates that plasmonic gold NPs can act as a booster to promote the grafting of diazonium derived aryl films at the gold NPs surface, in a confined nanoscale area. The laser irradiation is expected to generate a local heating, which can be sufficiently high to activate the thermal decomposition of diazonium salts and the resulting grafting of aryl layers, as described by M. Busson et al. This laser-induced thermal grafting could occur simultaneously with a plasmon-induced electron transfer and these two mechanisms should therefore be investigated separately to evaluate their respective efficiencies. Lithographic gold nanorod arrays were elaborated on an indium–tin-oxide coated-glass substrate by electron beam lithography.