A promising simple and effective,yet not well-explored method to tune the electronic structure of carbon graphene and other monolayer nanostructures is to employ weak interactions.In this talk,we will present our most recent adventure.(1)C-H…F-C Hydrogen Bonding in Graphane/Fluorographene(G/FG)Bilayer and CH/π Interactions in Graphene/C4H monolayer Bilayer The interlayer C-H…F-C hydrogen bonds,together with the external electric field(E-field),can effectively modulate the energy gap of graphene and fluorographene bilayer,1 but the desired high carrier mobility is lowered.In contrast,the CH/π interactions between graphene and its patterned partially(X4H)hydrogenated derivatives not only can introduce a sizable band gap,but also well preserve the high carrier mobility of graphene/silicene.2(2)Charge Transfer,Dihydrogen Bonds and Dihallogen Bonds in BN Nanosheets The interfacial charge transfer between BN nanosheets and the acceptor(tetracyanoquinodimethane,TCNQ)or donor(tetrathiafulvalene,TTF)molecule significantly reduces the intrinsic wide band gap of pristine BN nanosheets and consequently results in a p-or n-type semiconductor,respectively.The interlayer B-H…H-N dihydrogen bonds in the hydrogenated bilayer BN nanosheets and the B-X…X-N(X=F.Cl)dihallogen bonds in the halogenated bilayer BN nanosheets can also drastically reduce the intrinsic large band gaps of BN systems.These fascinating results illuminate a new pathway for band engineering of graphene and other monolayer nanomaterials.