In this thesis we studied two fundamental types of graphene nanoribbons (i.e., armchair and zigzag graphene nanoribbons) with bare edges and also with edges passivated by hydrogen atoms. Further, we studied in details the properties of nanoribbons doped by boron and nitrogen. Several con gurations of dopant atoms were chosen; these motifs have been tested in AGNNs and ZGNNs of different widths and with bare and passivated edges by hydrogen atoms. For calculations and modeling of magnetic properties of graphene nanoribbons we use Vienna ab initio simulation package.In this thesis we studied two fundamental types of graphene nanoribbons (i.e., armchair and zigzag graphene nanoribbons) with bare edges and also with edges passivated by hydrogen atoms. Further, we studied in details the properties of nanoribbons doped by boron and nitrogen. Several con gurations of dopant atoms were chosen; these motifs have been tested in AGNNs and ZGNNs of different widths and with bare and passivated edges by hydrogen atoms. For calculations and modeling of magnetic properties of graphene nanoribbons we use Vienna ab initio simulation package.