A nanoring is a cyclic nanostructure with a thickness small enough to be on the nanoscale (10−9 meters). Note that this definition allows the diameter of the ring to be larger than the nanoscale. Nanorings are a relatively recent development within the realm of nanoscience; the first peer-reviewed journal article mentioning these nanostructures came from researchers at the Institute of Physics and Center for Condensed Matter Physics in Beijing who synthesized nanorings made of gallium nitride in 2001.[2]Zinc oxide, a compound very commonly used in nanostructures, was first synthesized into nanorings by researchers at Georgia Institute of Technology in 2004, and several other common nanostructure compounds have been synthesized into nanorings since.[3] More recently, carbon-based nanorings have been synthesized from cyclo-para-phenylenes[4] as well as porphyrins.[5]