Experiments carried out to induce chirality into liquid crystals by means of photochemical procedures are reviewed. After basic considerations on the techniques used to detect supramolecular chirality in such organizations, the present Feature Article is focused on chiral photoinduction experiments performed on calamitic, columnar and bent-shaped liquid crystals. The most intense research corresponds to calamitic systems, either photochromic polymers or systems doped with a photoactive chiral trigger. Only recently have investigations on columnar or bent-shaped liquid crystals begun to receive attention.

Three light-sensitive amphiphiles, based on azobenzene, have been synthesized as supramolecular gelators. A hydrophobic chain with an azobenzene group incorporated at different positions was click coupled to a maltose polar head by a copper(I)-catalysed azide–alkyne [3 + 2] cycloaddition. The liquid crystalline and gel properties of these azo-amphiphilic materials have been studied. Two of these azo-gelators containing maltose give rise to stable gels in water or in a mixture of water and DMSO at room temperature. The chiral supramolecular assemblies of these gelators have been characterised by NMR, electron microscopy and circular dichroism (CD). The light-response of azo-amphiphiles in supramolecular gels has been studied. Also azo-gels, which contained mixtures of the azo-amphiphilic compounds and a similar structural hydrogelator, have been investigated.

Most of reported polymeric light-responsive nanocarriers make use of UV light to trigger morphological changes and the subsequent release of encapsulated cargoes. Moving from UV- to visible-responsive units is interesting for the potential biomedical applications of these materials. Herein we report the synthesis by ring opening polymerization (ROP) of a series of amphiphilic diblock copolymers, into which either UV or visible responsive azobenzenes have been introduced via copper(I) catalyzed azide-alkyne cycloaddition (CuAAC). These copolymers are able to self-assemble into spherical micelles or vesicles when dispersed in water. The study of the response of the self-assemblies upon UV (365 nm) or visible (530 or 625 nm) light irradiation has been studied by Transmission Electron Microscopy (TEM), Cryogenic Transmission Electron Microscopy (Cryo-TEM), and Dynamic Light Scattering (DLS) studies. Encapsulation of Nile Red, in micelles and vesicles, and Rhodamine B, in vesicles, and its light-stimulated release has been studied by fluorescence spectroscopy and confocal microscopy. Appreciable morphological changes have been induced with green light, and the subsequent release of encapsulated cargoes upon green light irradiation has been confirmed.

Racemic 2,8-diiodo-6H,12H-5,11-methanodibenzodiazocine (rac-1) and racemic 2,8-diiodoethynyl-6H,12H-5,11-methano-dibenzodiazocine (rac-2) proved to be self-complementary tectons that are particularly suitable for the formation of porous supramolecular structures by halogen bonding. Crystals structures of clathrate rac-1·CH₂Cl₂ and rac-2 show channels, which represent 20% of the cell volume, and these are stabilized by strong C–I⋯N and C–I⋯π_(Ar) halogen bonds.