Here we demonstrated a simple and straightforward way which can significantly improve the ORR activity of single walled carbon nanotubes (SWNTs) and graphene through adenine functionalization. Adenine can interact with CNTs and graphene's carbon planes, which draw electrons from adenine to make the N species form pyrrolic and graphitic-N, similar to N species of N doped materials. The activity for the ORR at a potential of −0.25 V vs. SCE was improved by 4.5 and 1.8 times, and the half-wave potential was around −0.25 V and 0.22 V vs. SCE for adenine functionalized SWNTs and graphene, which is 120 and 90 mV lower than Pt–C, respectively. Even though the activity and onset potential is smaller than that of commercial Pt–C, the results provide a simple and straightforward way to improve the activity of carbon materials through molecular functionalization in exploring C-based metal free electrocatalysts for ORR with better fuel selectivity, better CO tolerance and stability.