David Earl Nichols (born December 23, 1944, Covington, Kentucky) is an American pharmacologist and medicinal chemist. Previously the Robert C. and Charlotte P. Anderson Distinguished Chair in Pharmacology at Purdue University, Nichols has worked in the field of psychoactive drugs since 1969. While still a graduate student, he patented the method that is used to make the optical isomers of hallucinogenic amphetamines. His contributions include the synthesis and reporting of escaline, LSZ, 6-APB, 2C-I-NBOMe and other NBOMe variants (NBOMe-2C-B, NBOMe-2C-C, NBOMe-2C-D), and several others, as well as the coining of the term "entactogen".