Surface modification of materials is accomplished using a vast number of molecules that possess a special affinity (SAMS) or are prone to undergo chemical reactions with the surface groups of the substrate-usually hydroxylated oxide layers (phosphonic or carboxylic acids, silanes, etc.). Probably the most direct mode to achieve this task is the use of the diazonium salts. This surface modification permits an easy way for tuning the properties of materials and adding some new interesting functionality that can be explored for: sensor construction, corrosion protection, catalysis, etc. In this work, we explored the use of diazonium heterocyclic compound to graft the surface of the glassy carbon electrode through di electrochemical reaction of the transformed amino heterocyclic moiety into the corresponding diazonium salt. The grafted surface is analyzed by a number of electrochemical and surface analysis techniques.