As with MOCs and ACDAs, the thermodynamic product(s) formed from a dynamic combinatorial library will be determined by a balance of entropic and enthalpic effects. A significant component of these will be derived from the relative numbers and positions of the reactive functional groups in the sub-components. Whilst early seminal examples were assembled from condensation of aldehyde-functionalised cavitands with diamine linking units, 75 smaller, often commercially available, building blocks are now commonly used.