Piperazine scaffolds are amongst the most extensively used backbones in medicinal chemistry and many bioactive compounds are built upon this template. The physicochemical properties and the three-dimensional structures of the different piperazine chemotypes are of utmost importance to understanding its biological activities. Knowing the synthetic access to this chemical space of piperazines is of great importance to designing compounds with better properties. Isocyanide-based multicomponent reactions (IMCRs)allow for the truly convergent and efficient access to not less than 35 different piperazine derived scaffolds. These are reviewed, and their scopes and limitations are discussed. 1 Piperazine Scaffolds in Chemistry and Medicine 2 Chemical Space of Piperazines via Isocyanide-Based Multicomponent Reactions 3 Monocyclic Piperazines 3.1 Piperazine 3.2 Ketopiperazine 3.3 2,5-Diketopiperazine 3.4 2,6-Diketopiperazine 4 Bicyclic Fused Piperazines 5 Polycyclic Fused Piperazines 6 Introduction of the Piperazine Moiety via a Starting Material 7 Conclusions and Outlook. © 2010 Georg Thieme Verlag Stuttgart New York.