The thalidomide moiety of A6 was replaced by a photoswitchable lenalidomide-based cereblon (CRBN)-recruiter to obtain the desired PHOTACs. The synthesis of the photoswitch (outlined in Scheme 1A) was performed by dissolving lenalidomide (1) in hydrochloric acid followed by the addition of sodium nitrite to obtain the aryldiazonium salt 2. This intermediate was then exposed to a solution of 2,6-dimethoxyphenol to obtain the diazo compound 3. In the next step, compound 3 was treated with tert-butyl bromoacetate to obtain the photoswitchable CRBN ligand 4 via a nucleophilic substitution reaction. Firstly, the commercially available 2-CTC resin (5) was treated with N-hydroxyphthalimide to obtain the protected immobilized hydroxylamine 6. In the next step, the phthalimide protecting group was cleaved by treatment with hydrazine hydrate and the subsequent HATUmediated amide coupling with Fmoc-7-aminoheptanoic acid gave the intermediate 7.