BRD PHOTAC-I-3 is a photoswitchable BET bromodomain degrader (PHOTAC, PHOtochemically TArgeting Chimera). BRD PHOTAC-I-3 comprises a ligand for an E3 ligase, a photoswitch, and the BET bromodomain targeting ligand (+)-JQ1. Exhibits cytotoxicity and degrades BRD4, BRD3 and to a lesser extent BRD2 in lymphoblast cells upon irradiation with 390 nm light, but not in the dark.