IAP ligand 9 is a SMAC mimetic and binds to the IAP (inhibitor of apoptosis protein) BIR domains, selectively targeting cIAP1-BIR3 and XIAP-BIR3, while showing minimal affinity for XIAP-BIR2, with SPR pKD values of 7.0, 8.0, and 5.0, respectively. As an IAP ligand module, it can be conjugated via linkers with degraders targeting the TEAD1 P site to form IAP-recruiting proteolysis-targeting chimeras (PROTACs/IPDs). This IPD recruits the IAPE3 ubiquitin ligase to form the TEAD1-IPD-IAP ternary complex, mediating ubiquitination and proteasome-dependent degradation of TEAD1 and inducing autodegradation of cIAP1. IAP ligand 9 and related degraders are useful in the study of solid tumors such as malignant pleural mesothelioma associated with abnormal activation of the Hippo pathway.