This study demonstrated the design and synthesis of chiral or achiral polyimidazolium/poly-imidazolidium spherical particles. Particles with diameters in the range of nanometers to micrometers were formed spontaneously with certain spacer groups. The novel polymer particles have a rigid main-chain network structure. The parent ionic polymer particles could be easily transformed to stable poly-N-heterocyclic carbene (poly-NHC) particles and poly-NHC-metal organometallic particles with tailored chemical and physical properties. These colloidal nanoparticles and microparticles provided a unique platform for manipulating the versatile carbene chemistry. Poly-NHC-Pd particles exhibited excellent activity and recyclability in heterogeneous Suzuki cross-coupling reactions. (C) 2008 Elsevier Ltd. All rights reserved.