Drug-inducible regulation of multiple genes independently and simultaneously is a highly desirable gene therapy capability. Actuation of a plurality of genes with members of a common chemotype, rather than several unrelated chemotypes, could provide advantages in simplifying pharmacokinetics and pharmacodynamics, and could also potentially ameliorate possible undesired pleiotropic effects. Toward the goal of an orthogonal multiplex gene-switch using a single chemotype, a designed library of ca. 150 diacylhydrazine ligands was screened against a panel of ca. 50 wild-type and mutant ecdysone receptors (EcR) in a transcriptional activation assay using the EcRs fused to the GAL4 DNA binding domain in conjunction with a chimeric RXR fused to a VP16 activation domain. Luciferase was employed as a reporter gene, and the vectors were transfected into 3T3 cells. EC50 values for each receptor-ligand pair were obtained and multiple robust two-channel orthogonalities were observed. Structure activity relationships of both ligands and receptors are statistically meaningful and can be understood in the classical terms of medicinal chemistry.