The physical and chemical characteristics of nanomaterials are remarkable. They play a crucial part in the creation of cutting-edge therapeutics, catalytic materials, sensing technologies, and insecticides. Chemical and physical processes are often used to synthesize nanomaterials, although both involve the use of very hazardous substances or significant amounts of energy. Green synthesis, in which molecules derived from microbes, animals, and plants are employed as waste reducers and nanomaterial stabilizers, has lately been the focus of scientific attention as a step towards more ecologically friendly procedures. It has been suggested that using green synthesis approaches, which are less expensive and less harmful tothe environment, would allow for the creation of nano-objects with precisely tunable dimensions and morphologies that will improve their bioactivity. Unfortunately, there is a dearth of green-fabricated nanomaterials on the market, and their potential uses in the real world have only just begun to be studied. Several of our assumptions regarding their primary mechanisms of action and their non-target toxicity may need to be revised. Concerns about their potential environmental destiny are raised by such inquiries. In this context, the current Special Issue features articles by eminent researchers on many aspects of nano synthesis. The papers in this Special Issue address some of the most critical and topical questions in green nanomaterial research. The vast majority of the content is comprised of first-hand accounts of research conducted by the authors themselves, and it all focuses on theoretical principles and practical procedures that are relevant to the use of nanomaterials in the real world.