Conjugated polymers with strong photophysical properties are used in many applications. A homopolymer (P1) and five new low band gap copolymers based on 4,4'-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) and acceptors 3,6-dithienyldiketopyrrolopyrrole (P2), phthalimide (P3), benzotriazole (P4), 4,7-dithienyl[1,2,3]triazolo[4,5g]quinoxaline (P5), and 2,5-dithienylthieno[3,4-b]pyrazine (P6) were prepared by means of Sonogashira polymerization. The characterization of polymers by using (1) H NMR, absorption, and emission spectroscopy is discussed. All polymers with high molecular weights (Mn ) of 16 000 to 89 000 g mol(-1) showed absorption maxima in the deep-red region (λ=630-760 nm) in solution and exhibited significant redshifts (up to 70 nm) in thin films. Polymers P2, P5, and P6 showed narrow optical band gaps of 1.38, 1.35, and 1.38 eV, respectively, which are significantly lower than that of P1 (1.63 eV). The HOMO and LUMO energy levels of the polymers were calculated by using cyclic voltammetry measurements. The LUMO energy levels of BODIPY-based alternating copolymers were independent of the acceptors; this suggests that the major factor that tunes the LUMO energy levels of the polymers could be the BODIPY core. All polymers showed selective and reproducible detection of volatile organic solvents, such as toluene and benzene, which could be used for developing sensors.

BODIPY-based hyperbranched polymer showed improved selectivity and sensitivity for toluene as originated from the strong π–π interaction and high porosity within polymer matrix.

The self-assembly of photochromic dithienylethene molecules into circular nanostructures is reported. The formation of nanostructures is dependent on factors such as photoisomerization, solvent, and hydrogen bonding.

A solution-based chemical synthesis of two graphene nanoribbons with armchair edges is reported. The precursor oligophenylene molecules are synthesized and subjected to oxidative cyclodehydrogenation to afford the target molecules, G-1 and G-2. These molecules have good solubility in organic solvents, and show a large redshift in their absorption edge (up to 185 nm) and emission maximum (up to 125 nm) after planarization. Fibrous structures are formed upon self-assembly of molecules through columnar π-π stacking. Such molecular assemblies may be useful for various applications.

A series of soluble 3D-oligothiophenes with different conjugation lengths are synthesized and characterized. Physical properties and formation of charge transfer complexes of oligothiophenes with Hg(ii) ions and TCNQ are investigated.