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Two-dimensional(2D)materials show many fascinating properties,however,different 2D materials are required for different applications.The controlled synthesis and applications of graphene materials will be first discussed,including chemical vapor deposition(CVD)growth of large-area high-quality graphene single crystals,films and their applications in flexible touch panels and OLEDs,CVD growth of highly conductive flexible three-dimensional graphene network structures and their applications in elastic conductors,flexible lithium ion batteries(LIBs)with ultrafast charge and discharge rates,lightweight and flexible electromagnetic interference shielding materials,and flexible high-energy lithium sulfur batteries,and large-scale production of highly conductive pristine graphene nanosheets by intercalation-exfoliation method and their applications in LIBs,lithium sulfur batteries,anti-corrosion coatings,and thermal management.In addition to graphene,other 2D materials have recently attracted increasing interest because of their properties that are complementary to graphene.Transition metal carbides(TMCs)are a large family of materials that combine the properties of ceramics and metals,however,the 2D TMCs obtained so far are chemically derived functionalized and defective nanosheets.In the second part,I will show the CVD growth of large-size high-quality ultrathin 2D TMC crystals.For instance,the 2D α-Mo2C crystals obtained are a few nanometers thick,over 100 m in lateral size,and very stable under ambient conditions.They show 2D characteristics of superconducting transitions that are consistent with Berezinskii-Kosterlitz-Thouless behavior and show strong anisotropy with magnetic field orientation,and strong dependence of superconductivity on thickness of the crystals.These ultrathin TMC crystals expand the large family of 2D materials.