tert-Butyl (2-((4-((4-Aminophenyl)diazenyl)phenyl)amino)-2-oxoethyl)(4-hydroxy-3,5-diisopropylbenzyl)carbamate is an intermediate used in the synthesis of MTS PHOTO-SWITCHABLE Compound (M125115), which is a derivative compound of Maleidopropionic acid (M140750), a sulfhyryl reactive heterobifunctional crosslinking reagent.