2C-I or 2,5-dimethoxy-4-iodophenethylamine is a psychedelic phenethylamine of the 2C family. It was first synthesized by Alexander Shulgin. It was described in Shulgin’s book PiHKAL: A Chemical Love Story. The drug is used recreationally for its psychedelic and entactogenic effects. 2C-I is commonly sold in its hydrochloride salt form, which is a fluffy, sparkling-white powder, which has also been pressed into tablet form.

In the early 2000s (decade), 2C-I, otherwise known as "smith", was sold in Dutch smart shops, after 2C-B, which was previously sold, was banned. In April 2008, 2C-I was also banned in the Netherlands, along with three other 2C-x phenethylamines previously sold in Dutch smartshops for short periods of time. During the same period, 2C-I also became available in powder form from several online vendors of research chemicals in the United States, Asia, and Western Europe. In 2002 and 2003, tablets of 2C-I were being sold in nightclubs and at raves in Denmark and in the United Kingdom as a club drug.