FFN511 (hydrochloride) is a potent fluorescent false neurotransmitters (FFNs) that targets neuronal vesicular monoamine transporter 2 (VMA T2). FFN511 (hydrochloride) inhibits serotonin binding to VMA T2 -containing membranes with an IC 50 of 1 µM. FFN511 (hydrochloride) directly images the dynamics of release during exocytosis, can be used to label dopamine terminals in live cortical-striatalacute slices.