Fluorinated single-layer diamond (“F-diamond”) is a new form of two-dimensional (2D) carbon allotrope. Herein, poly(dicarbon monofluoride) (C2F)n which is essentially made of stacked layers of “F-diamane” has been synthesized and exfoliated in a variety of solvents to yield well-dispersed ultrathin sheets. Microscopic and spectroscopic analyses revealed that the exfoliated nanosheets retained the “F-diamane”-like structure. The experimental results are also supported by density functional theory (DFT) calculations.