Aromaticity of Caffeine In the Caffeine molecule, is aromaticity confined only to the 5 membered ring? The entire molecule is planar and the 6 membered ring also seems to have 6π electrons.
The entire molecule has 10π electrons.(inside)
No. The 6 membered ring is also a part of its aromaticity.
This can be better understood by considering the Zwitterion of Caffeine.

The entire molecule is planar, conjugated and has 10π electrons(4n+2)
Reference:Slides by Nevina Keskineva