Book excerpt: 2D Monoelements: Properties and Applications explores the challenges, research progress and future developments of the basic idea of two-dimensional monoelements, classifications, and application in field-effect transistors for sensing and biosensing. The thematic topics include investigations such as: Recent advances in phosphorene The diverse properties of two-dimensional antimonene, of graphene and its derivatives The molecular docking simulation study used to analyze the binding mechanisms of graphene oxide as a cancer drug carrier Metal-organic frameworks (MOFs)-derived carbon (graphene and carbon nanotubes) and MOF-carbon composite materials, with a special emphasis on the use of these nanostructures for energy storage devices (supercapacitors) Two-dimensional monoelements classification like graphene application in field-effect transistors for sensing and biosensing Graphene-based ternary materials as a supercapacitor electrode Rise of silicene and its applications in gas sensing