A straightforward synthesis of the fused-aromatic dione benzo[1,2-b:6,5-b']dithiophene-4,5-dione (BDTD) has been developed. This fused-aromatic dione was subjected to various chemical transformations to generate diverse molecules with potential use in π-conjugated materials for organic electronics.

We describe the synthesis of three tetraureacalix[4]arenes having four appended terminal azobenzene groups. In CD2Cl2 solution and at millimolar concentration, the thermally equilibrated all-trans-tetraureas dimerize quantitatively, encapsulating one Me4P(+) cation. The light-induced isomerization of the all-trans encapsulation complexes produced a plethora of isomeric cis-enriched counterparts displaying a reduction in cavity size. cis-enriched dimers not suitable for the encapsulation of the cation or a solvent molecule are also produced, leading to partial release of the cargo (Me4P(+)) to the bulk solution. The substitution of the terminal phenyl in the azobenzene groups plays a key role in controlling the amount of released cargo in quantities up to 70%. The switching between the two states (all-trans and cis-enriched capsules) proceeds with no detectable photodegradation, even when it is repeated multiple times.

An effective decarboxylative cross-coupling involving a 3,4-dioxypyrrole is reported. Several conjugated oligomers were synthesized in high yields using various aryl bromides. No copper salt or other transmetalating agent was required. The reaction conditions employed displayed relatively low sensitivity toward the presence of water.

Heterodimeric capsules self-assembled from tetraurea calix[4]pyrrole and tetraurea calix[4]arene provide unique molecular containers for the organised inclusion of small polar molecules. By inserting stimuli-responsive groups (azobenzene) in the heterocapsule structure, we are able to modify the equilibrium state of the system or the exchange between different host-guest assemblies in a reversible manner.