2C-BI-8, also known as 2,5-dimethoxy-4-(4-methoxyphenyl)phenethylamine or as 4â²-methoxy-2C-Ph, is a serotonin receptor agonist of the phenethylamine and 2C families. It is the derivative of 2C-Ph (2C-BI-1) with a methoxy group at the 4 position of the added phenyl ring.
The drug binds to and/or activates the serotonin 5-HT<sub>2</sub> receptors. At the human serotonin 5-HT<sub>2A</sub> receptor, its affinity (K<sub>i</sub>) is 19nM, activational potency () is 37nM, and intrinsic activity () is 40%. These were among the most potent and efficacious in a series of evaluated 2C-Ph derivatives (2C-BI compounds) that included 2C-BI-8. However, 2C-BI-8's activational potency was about 18-fold lower than that of 2C-B and its efficacy was less than half of that of 2C-B. The drug also interacts with certain other monoamine receptors and has been assessed at the monoamine transporters. It may have the potential to produce psychedelic effects in humans.
2C-BI-8 was first described in the scientific literature by Daniel Trachsel and David E. Nichols and colleagues in 2009. It is a controlled substance in Canada under phenethylamine blanket-ban language.