▎ 摘　　要

In the present review article we discuss the progress that has been thus far achieved towards producing graphene nanoribbons (GNRs) with predefined dimensions and, therefore, electronic properties, by using bottom-up approaches. Some selected, representative top-down strategies are also reviewed. GNRs are graphitic carbon-based materials having nano-scale dimensions and semiconducting or metallic electronic properties depending on their geometry and dimensions. These GNRs electronic characteristics are in sharp contrast to those of graphene, the parent graphitic material, which is an atomically-thick carbon sheet with semimetal, zero band gap characteristics.