Phenethylamines are characterized by their simple, yet elegant, chemical structure. The core structure consists of a phenethylamine backbone, which can be modified with various substituents to produce a wide range of psychoactive effects. Shulgin's work highlights the incredible diversity of phenethylamines, with compounds ranging from the relatively simple 3,4-methylenedioxymethamphetamine (MDMA) to the more complex 2C-B, a psychedelic compound with a unique profile.