Nanoparticles and nanostructures represent fundamental elements in the field of nanotechnology, characterized by their ultra-small dimensions and exceptional surface-to-volume ratios. These nanoscale materials exhibit distinctive optical, electrical, magnetic, and catalytic properties that enable breakthroughs across multiple scientific domains, including biomedicine, electronics, energy, and environmental science. Nanoparticles—typically spherical or near-spherical—are widely used in drug delivery, imaging, and sensing, while nanostructures such as nanowires, nanotubes, nanorods, and nanosheets provide tailored architectures for device fabrication and functional interfaces. The precise engineering of these materials at the atomic and molecular level allows for unprecedented control over performance and reactivity. Ongoing research in synthesis, characterization, and application of nanoparticles and nanostructures continues to drive transformative innovations in both fundamental science and practical technologies.