Our potent and selective hA₃ adenosine receptor fluorescent antagonist shows a high affinity and selectivity for hA₃ receptor over the other receptor subtypes (K_i = 6.13 nM for A₃ receptor in radioligand binding assay). It allows to perform cell visualization in fluorescence microscopy, confocal microscopy and high content system experiments. It is potentially suitable for other fluorescence-based assays.