Our potent and fully selective human 5-HT₂A serotonin receptor fluorescent ligand shows high affinity for 5-HT₂A receptor (K_i = 6.2 nM in radioligand binding assay) over the other receptor subtypes. 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.