2C-G-3, also known as 2,5-dimethoxy-3,4-(trimethylene)phenethylamine, is a psychedelic drug of the phenethylamine and 2C families. It is the derivative of 2C-G (2C-G-0) in which the 3,4-dimethyl groups have been connected via an additional carbon atom to form a cyclopentane ring attached to the benzene ring and hence has a dihydroindene ring system.
In his 1991 book PiHKAL (Phenethylamines I Have Known and Loved) and other publications, Alexander Shulgin lists 2C-G-3's dose as 16 to 25mg orally and its duration as 12 to 24hours. The effects of 2C-G-3 were reported to include "lots of LSD-like sparkles", easier communication, impairment, and social avoidance, among others. One report remarked that it was "marvelous".
The chemical synthesis of 2C-G-3 has been described.
The drug was first described in the literature by Shulgin in PiHKAL in 1991. It is a controlled substance in Canada under phenethylamine blanket-ban language.