Graphene nanoribbons(GNRs)have a bandgap which can be tuned by controlled doping.Using the on-surface synthesis technique,atomically precise nitrogen-doped and sulfur-doped graphene nanoribbons have been fabricated on Au(111)surfaces.Scanning tunneling microscopy/spectroscopy and density functional theory calculation results indicate that the cyclodehydrogenation of the precursors generates several distinct types of building blocks for GNRs synthesis and these building blocks have different energy gaps.The GNRs constructed by these different building blocks was confirmed to be type-Ⅰ heterojunctions.