Potent and selective dopamine D1 receptor positive allosteric modulator (Kb = 11.4nM and EC50 = 5.8nM in human D1 receptors). Suitable for use with genetically encoded dopamine sensors to enhance their sensitivity. When used with the dLight1.3b genetically encoded dopamine sensor, DETQ administration leads to an 8-fold increase in dopamine sensitivity (2µM to 244nM) with a Kb of 54nM. Due to a 30-fold lower affinity for rodent D1 receptors (Mouse D1: Kb = 312nM) compared to human (Kb = 11.4), DETQ is suitable for chemogenetic modulation of human based dopamine sensors in rodents. No cross-reactivity observed with D2, D5, β2, 5HT6 receptors. DETQ reverses reserpine induced locomotor deficits alongside increasing PFC histamine and acetylcholine concentrations in human D1 expressing mice. Orally bioavailable, active in-vivo and blood brain barrier permeable.