Single gold adatoms were manipulated on a Au(111) surface with the tip of a scanning tunnelling microscope to contact selected peripheral p bonds of a single Coronene molecule. Tunnelling electron spectroscopy and differential conductance mapping of the Au-Coronene complexes show how Coronene's electronic ground state is shifted down in energy as the function of the number of interacting Au atoms, demonstrating that a Coronene molecule can function like a single molecule counter. The number of interacting atoms can be counted by simply following the linear energy downshift of Coronene's ground state. (C) 2013 Elsevier B. V. All rights reserved.