Many naturally occurring systems show us how multi-component supramolecular assemblies can generate useful functional behaviour. In this article the problems and limitations associated with achieving such behaviour in artificial multi-component assemblies is discussed, together with two examples of functions in artificial supramolecular assemblies based on (i) host–guest chemistry in cavities of cages, and (ii) light-harvesting in multi-chromophore arrays. Important challenges for the future are summarised.

A methodology has been developed for characterising hydrogen-bonded ring motifs formed between two organic molecules without any prior knowledge of the topology or chemical constitution of the motifs. The method has been implemented by modifying the current Cambridge Structural Database (CSD) System programs. All intermolecular ring motifs comprising ⩽20 atoms formed with N—H···N, N—H···O, O—H···N and O—H···O hydrogen bonds in organic structures in the CSD have been classified. The 75 bimolecular motifs occurring in >12 structures in the CSD are described in terms of their graph sets and chemical functionalities. Motifs are ranked according to their frequency of occurrence and according to their probabilities of formation, i.e. their frequency relative to the number of possible motifs which could have formed. These probabilities provide insights into the relative robustness of known and potential supramolecular synthons.

The design and development of functional materials with real-life applications are highly demanding. Understanding and controlling inter- and intra-molecular interactions provide opportunities to design new materials. A judicious manipulation of the molecular structure significantly alters such interactions and can boost selected properties and functions of the material. There is burgeoning evidence of the beneficial effects of non-covalent interactions (NCIs), showing that manipulating NCIs may generate functional materials with a wide variety of physical properties leading to applications in catalysis, drug delivery, crystal engineering, etc. This prompted us to review the implications of NCIs on the molecular packing, optical properties, and applications of functional π-conjugated materials. To this end, this tutorial review will cover different types of interactions (electrostatic, π-interactions, metallophilic, etc.) and their impact on π-conjugated materials. Attempts have also been made to delineate the effects of weak interactions on opto-electronic (O-E) applications.

Soluble, rigid-rod organometallic polymers trans-$\mathrm{[-}\mathrm{Pt}({\mathrm{PBu}}_3^n{)}_2–\mathrm{C\equiv C–R–C\equiv C}{\mathrm{–]}}_{\infty }$ ($\mathrm{R=bithienyl}$ 2, terthienyl 3) have been synthesized in good yields by the CuI-catalyzed dehydrohalogenation reaction of trans-$[\mathrm{Pt}({\mathrm{PBu}}_3^n{)}_2{\mathrm{Cl}}_{\mathrm{2}}]$ with one equivalent of the diterminal alkynyl oligothiophenes $\mathrm{H–C\equiv C–R–C\equiv C–H}$ in ${\mathrm{CH}}_{\mathrm{2}}{\mathrm{Cl}}_{\mathrm{2}}{\mathrm{/}}^{\mathrm{i}}{\mathrm{Pr}}_{\mathrm{2}}\mathrm{NH}$ at room temperature. We report the thermal properties, and the optical absorption, photoluminescence, and photocurrent action spectra of 1 (trans-$\mathrm{[–}\mathrm{Pt}({\mathrm{PBu}}_3^n{)}_2–\mathrm{C\equiv C–R–C\equiv C}{\mathrm{–]}}_{\infty },$ $\mathrm{R=thienyl}$ ), 2 and 3 as a function of the number of thiophene rings within the bridging ligand. With increasing thiophene content, the optical gap is reduced and the vibronic structure of the singlet emission changes toward that typical for oligothiophenes. We also find the intersystem crossing from the singlet excited state to the triplet excited state to become reduced, while the singlet–triplet energy gap remains unaltered. The latter implies that, in these systems, the $T_1$ triplet excited state is extended over several thiophene rings. The photoconducting properties do not depend on the size of the thiophene fragment. We discuss and compare our results with studies on oligothiophenes and related organometallic polymers.