Ionizable cationic lipids are a key component in the formulation of lipid nanoparticles (LNPs). Ionizable cationic lipids encapsulate nucleic acid payloads and promote endosomal escape with minimal cytotoxicity. Given the significant structural and functional diversity of these lipids, ionizable cationic lipids have utility in several LNP applications, from achieving tissue tropism for targeted delivery to personalized cell and gene therapy.