The thermal treatment of a monolayer of 1-naphthylmethylamine (NMA) on Ni(1 1 1) surface reveals a complex chemistry promoted by the high surface reactivity. Both the amino-terminated functional group and the naphthalene body of NMA undergo a progressive dehydrogenation, which eventually leads to the coalescence of the molecules. As a result, 2D structures of increasing size are synthesized on the surface, characterized by a graphene-like lattice in which nitrogen atoms are mainly incorporated as pyridinic substitutional defects. In this paper, we show the evidence of the formation of extended nitrogen-doped graphene (N-GR) domains at temperatures as low as 300 °C, with band dispersion measurements that reveal p-type doping.