A review.Constitutionally isomeric peptides are a class of mols. with the same composition but different connections, ultimately exhibiting a significant variation in properties.In this review, we survey the recent advances in the rational design of constitutionally isomeric peptides and the preparation of discrete assemblies.Then, we examine their applications as templates for inorganic nanoparticle growth, biofilm elimination, or carriers for on-demand gas/drug delivery.At the end, both future outlooks and upcoming challenges of this emerging research topic are also discussed.It is our hope that the review will give insight into how subtle modulation in the peptide sequence would generate a dramatic change in the resultant property.