A Photochemical reactor is a device that uses light (Photon) to perform a chemical reaction. Typically, the chemical reactions need a high temperature (about 100 to 250 degrees Celsius) for a large production scale. However, this process also gives useless byproducts and losses. With the help of a photoreactor, the process of material synthesis becomes easy. It is efficient and does not produce unwanted byproducts. Mainly this reaction carries out in the presence of photon and catalyst; hence it is called a Photocatalytic reactor. The process of photochlorination, water splitting, aflatoxin production, sulfonation, sulfoxidation, and nitrosylation can be performed successfully using this reactor setup. The reactor is also known as a UV reactor because the “light” we talk about here is commonly ultraviolet light. Comparing it to the traditional methods is much more reliable, consistent, and precise and gives opportunities to explore photochemistry.