Abstract: The invention relates to a method for preparing cucurbiturils. The method comprises reacting an oligomer consisting of 2 to 11 linked glycolurils or glycoluril analogues with one or more compounds selected from glycoluril, glycoluril analogues and/or oligomers of glycoluril or glycoluril analogues, in the presence of an acid, to form a cucurbituril. The method can be used to prepare variably substituted cucurbiturils having specific substituted units at specific locations in the cucurbituril. The invention also provides cucurbiturils prepared by the method of the invention. The invention further provides novel cucurbiturils.