It is shown how the surface of graphite can be treated with chromic oxide in order to attach acid groups. It then becomes possible to attach molecules that contain basic functionalities to the graphite surface. The presence and orientation of the attached molecules are characterized by Auger, IR, UPS, and XPS spectroscopies. Copper tetraazaphthalocyanine is studied in detail because a few molecules of this compound produce rectification of electric current in a scanning tunneling microscope.