In this report, flower-like Au nanochains were facilely prepared by a one-step synthesis with the assistance of caffeine as a structure directing and weak stabilizing agent. It was found that the reaction temperature and the ratio of [caffeine]/[HAuCl₄] were the key factors during the synthesis process, and their growth mechanism was discussed in some detail. The as-prepared Au superstructures displayed an excellent catalytic ability towards the reduction of p-nitrophenol, which showed potential applications in the construction of optical and catalytic devices.