In this paper, a new electrochemical sensor based on a new fluorescent probe N-(2-(1-(p-tolyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)picolinamide (Pi-A) decorated reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) was developed for highly selective detection of copper ions using the electrochemical method.