Two‐dimensional van der Waals heterostructures possess potentials of atomic‐layer thick p‐n junctions for ultrathin optoelectronics. The tungsten diselenide becomes one of the most important building blocks because of its p‐type charge carrier conductivity. To date, strict monolayer tungsten diselenide film is still required. Jinbo Pang, Hong Liu, Gianaurelio Cuniberti and Mark H. Rummeli reported a synthesis approach to achieve monolayer tungsten diselenide with sub‐1 cm homogeneity, titled High‐performance electronics and optoelectronics of monolayer tungsten diselenide full film from pre‐seeding strategy (DOI: 10.1002/inf2.12259 ). In this cover, tungsten oxides were first deposited over the substrates by dip‐coating methods (top right). Then, tungsten oxides nanoparticles act as heterogeneous nucleation sites, which transform to tungsten diselenide upon selenization and grow to form larger individual grains (Middle left). After the incorporation of tungsten oxides and selenium vapor sources, WSe 2 domains continue to increase and coalesce into seamless full‐coverage monolayer film (bottom background), featured self‐limiting mechanism. image