Our potent and selective hα_1A  adrenergic receptor fluorescent antagonist shows high affinity for α_1A adrenergic receptor (K_i = 28.3 nM measured in radioligand binding assay) and selectivity over α_2A (K_i = 1081 nM measured in radioligand binding assay). It is potentially suitable for fluorescence-based assays such as confocal microscopy or high content screening.