  For the first time bis-functionalization of graphene employing two successive
reduction and covalent bond formation steps are reported. Both bulk
functionalization in solution and functionalization of individual sheets
deposited on surfaces have been carried out. Whereas in the former case attacks
from both sides of the basal plane are possible and can lead to strain-free
architectures, in the latter case, retro-functionalizations can get important
when the corresponding anion of the addend represents a sufficiently good
leaving group.
