Fluorescent carbon dots (CDs) are emerging nanomaterials with exceptional optical properties, biocompatibility, and versatile applications in biomedical imaging, drug delivery, environmental sensing, and catalysis. CDs, characterized by their small size and unique fluorescence, can be synthesized using top-down or bottom-up approaches, offering control over their size, structure, and surface functionalization. Their ability to provide high-resolution imaging, targeted drug delivery, and efficient pollutant detection highlights their multifunctionality. Despite their vast potential, challenges such as scalability and reproducibility remain barriers to widespread application. activated carbon was chemically prepared using Peach crusts (agriculturalwaste) as renewable resource.The prepared activated carbon wasmodified by introducing two transition metal ions in its framework; Mn and Fe metal ions. This minireview explores advancements in CDs synthesis methods and highlights their transformative role in nanotechnology, medicine, and environmental science. Unlike green diesel, biodiesel can only be used in diesel engines blended with diesel in order to avoid excessive build-up of carbon in diesel engines. Therefore, production of green fuel from catalytic cracking is getting more attention.