Organic compounds, which are based on carbon, exhibit a wide range of colors depending on their molecular structure and functional groups. While many organic compounds are colorless, others display vibrant hues. For instance, aromatic compounds often have distinct colors due to their conjugated π-electron systems. For example, benzene is colorless, but when it is substituted with certain groups like nitro (-NO2) or halogens, it can turn yellow, orange, or red, respectively. Additionally, certain organic compounds, such as copper phthalocyanine, are known for their deep blue color, which is widely used in pigments and dyes. The color of organic compounds is influenced by factors like conjugation, aromaticity, and the presence of certain functional groups, which can absorb light at specific wavelengths, leading to the observed color. According to a study by the Royal Society of Chemistry, the color of organic compounds is a result of electronic transitions within the molecule, which can be influenced by the molecular structure and the environment in which the compound exists.