2C (2C-x) is a general name for the family of psychedelic phenethylamines containing methoxy groups on the 2 and 5 positions of a benzene ring. Most of these compounds also carry lipophilic substituents at the 4 position, usually resulting in more potent and more metabolically stable and longer acting compounds. Most of the currently known 2C compounds were first synthesized by Alexander Shulgin in the 1970s and 1980s and published in his book PiHKAL (Phenethylamines i Have Known And Loved). Shulgin also invented the term 2C, being an acronym for the 2 carbon atoms between the benzene ring and the amino group.

2C or II-C may refer to:

• 2C (psychedelics), a family of psychedelic phenethylamines
• Alpha-2C adrenergic receptor in biochemistry
• Char 2C, a French heavy tank developed during World War I
• Long March 2C, a Chinese rocket
• Oflag II-C, a World War II German Army Prisoner-of-war camp located near Woldenburg
• 2 cents (disambiguation), a coin in certain realms
• Second Cambridge Catalogue of Radio Sources
• Two's complement, a system for representing signed integers on computers
• 2C Media, a television production company based in Miami, Florida