The design and synthesis of new macrocyclic compounds always represent one of hot research fields in supramolecular chemistry. The development of classical macrocyclic compounds, such as crown ether, cyclodextrin, calixarene, cucurbituril and pillararene, enriches the contents of supramolecular chemistry. Meanwhile, the functionalizated macrocyclic compounds have been successfully used to create a number of applications including chemical sensors, molecular machines, biomimetic systems, supramolecular catalysts, stimuli-responsive systems, functional materials and drug delivery. Cucurbit uril bearing a rigid and hydrophobic cavity has gained great attention for its unique recognition property in water. Compared to that of other macrocyclic compounds, however, the functionalization of cucurbit uril is more difficult due to their chemical inertness. In the past few years, numerous efforts have been devoted to functionalize cucurbit uril and develop their host-guest recognition property not only in supramolecular chemistry, but also bio-chemistry, material chemistry, and medicinal chemistry. This review mainly focuses on summarizing the research progress of functionalized cucurbit uril, and comments on the bright future of their synthetic methods briefly.

Contents
1 Introduction
2 Condensation of substituted glycoluril with formaldehyde
3 Condensation of substituted glycoluril biether with glycolril
4 Condensation of substituted glycoluril biether with glycoluril oligomers
5 Oxidation of cucurbit[n]uril
6 Condensation of glycoluril oligomers with substituted aldehydes
7 Conclusion