4-bromo-2,5-dimethoxyphenethylamine (Bromodimethoxyphenethylamine or 2C-B) is a psychedelic drug of the 2C family. It was first synthesized by Alexander Shulgin in 1974. In Shulgin's book PiHKAL, the dosage range is listed as 16–24 mg. 2C-B is sold as a white powder sometimes pressed in tablets or gel caps and is referred to on the street as 'Bees' or 'Nexus'. The drug is usually taken orally, but can also be insufflated or vaporised.

2C-B was synthesized from 2,5-dimethoxybenzaldehyde by Alexander Shulgin in 1974. It first saw use among the psychiatric community as an aid during therapy. It was considered one of the best drugs for this purpose because of its short duration, relative absence of side effects, and comparably mild nature. Shortly after becoming popular in the medical community, it became popular recreationally. 2C-B was first sold commercially as an aphrodisiac under the trade name "Eros", which was manufactured by the German pharmaceutical company Drittewelle. For several years, it was available in Dutch smart shops under the name "Nexus" as predosed tablets, however, it was placed on List I of the Opium Law after being sold without any incidents occurring, which led to the replacement of 2C-B by other phenethylamine psychedelics like 2C-I, 2C-T-2 and 2C-T-7 that were not controlled substances in the Netherlands at the time (but were banned later by the Dutch government, after being sold in smartshops for short periods).