Oxime, whose dynamic nature was reported to be switchable between ON/OFF by tuning the acidity, is employed in a novel type of dynamic covalent approach that is amenable to use in water for self‐assembly of purely organic molecules with complex topology. In strongly acidic conditions, the dynamic nature of oxime is turned ON, allowing occurrence of error‐checking and therefore a catenane and a macrocycle self‐assembled in high yields. In neutral conditions, oxime ceases to be dynamic, which helps to trap the self‐assembled products even when the driving forces of their formation are removed. We envision that this switchable behaviour might help, at least partially, to resolve a commonly encountered drawback of dynamic covalent chemistry, namely that the intrinsic stability of the self‐assembled products containing dynamic bonds, such as imine or hydrazone, are often jeopardized by their reversible nature.

A macrocycle through a dynamic covalent approach relying on reversible hydrazone formation in acidic aqueous solutions at elevated temperatures is constructed. By decreasing the acidity of the solution and lowering the temperature, the structure becomes kinetically inert. The macrocycle is capable of hosting hydrophobic aromatic guest molecules in water.

Using a novel dynamic covalent approach relying on reversible hydrazone formation, a purely organic 3-dimensional prismatic cage was developed in water at elevated temperatures. By lowering the temperature, the hydrazone bond becomes kinetically inert. This self-assembled cage acts as an effective receptor for donor-acceptor pairs, whose interactions are weak in the absence of the cage.

By condensing a trisamino linker with one of the two analogous bisaldehyde ligands, pills and tetrahedrons could be self-assembled. The self-assembled preference could be controlled by tuning the reaction conditions, including the size of side chain, concentration, and temperature. Coordination of silver cation quenches the fluorescence of the fluorene moieties on the pill, opening up opportunities for Ag+ cation detection.

Spin–spin interactions between two identical aromatic radicals have been studied extensively and utilized to establish supramolecular recognition. Here we report that spin-pairing interactions could also take place between two different π-electron radicals, namely a bipyridinium radical cation (BPY+•) and a naphthalene-1,8:4,5-bis(dicarboximide) radical anion (NDI─•). The occurrence of this type of previously unreported hetero radical-pairing interactions is attributed to enhancement effect of Coulombic attraction between these two radicals bearing opposite charges. The Coulombic-enhanced hetero radical pairing interactions are employed to drive host–guest recognition, as well as the reversible switching of a bistable [2]rotaxane.