The chemical doings in graphitic systems have been extensively studied both experimentally and theoretically since 1984. From the viewpoint of geometric structure, each graphene nanoribbon is regarded as a finite-width graphene strip or an unzipped carbon nanotube. Graphene nanoribbons have been successfully produced by various experimental techniques. Cutting graphene could be achieved by using metal catalysts, oxidation lithographic patterning and etching, and sonochemical breaking. The essential properties of alkali-adsorbed graphenes are investigated for the distinct adatoms, concentrations, and distributions. All the alkali-adsorbed graphenes exhibit the alkali-and carbon-dominated energy bands, accompanied with a modified Dirac-cone structure. According to the theoretical predictions, each alkali atom can contribute one conduction electron to graphene-related systems and thus create very high free carrier densities. Lithium intercalation between graphene layers can create the highest conductivity and transparency so far among all thin-film materials to date. The instability in air of lithium intercalated graphene can be improved by using an air-tight sealing.