▎ 摘　　要

Controllable edge-selective modification and tailoring of graphene are particularly critical for graphene appli-cations. In this study, precise edge functionalization and tailoring of graphene are realized by a solvent -controlled Friedel-Crafts acylation reaction. Specifically, experimental and theoretical studies demonstrate that solvent effects can effectively control the reaction pathways of substituent and ionic mechanisms. Under the substituent mechanism, carboxyl groups are accurately introduced to the edge of graphene, which can be used as new reaction sites for further modification. Under the ionic mechanism, the acylation process can further tear graphene to the desired size. When the reaction is sufficient, graphene can be torn into highly dispersed high -quality quantum dots on a scale of 5 nm. This edge-and size-controllable fabrication method expands poten-tial applications of graphene, such as electronic devices, semiconductors, catalysis and batteries.