Conjugated 1,4-bis(n'-quinolyl)-1,3-butadiynes were obtained through the oxidative dimerization of the corresponding n'-ethynylquinolines catalyzed by cuprous chloride. Differential scanning calorimetry analysis of the 1,4-bis[n'-(quinolyl)]buta-1,3-diyne molecules produced evidence of a syn-anti rotational equilibrium around the 1,3-diyne axis and an irreversible transformation into a thermopolymer. The topooligomerization of 1,4-bis[3'-(quinolyl)]buta-1,3-diyne, which took place by irradiation with sunlight, was investigated with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Accurate X-ray molecular structure and refinement analysis of 1,4-bis[3'-(quinolyl)]buta-1,3-diyne was conducted. The molecular crystalline packing consisted of parallel arrays of two groups of centrosymmetric molecules (antirotamer) in a herringbone assemblage in the solid state. The polymerization of 3-ethynylquinoline was carried out with the AlEt3/V(acac)(3) system to produce a mixture of 1,2,4- and 1,3,5-tris(3'-quinolyl)benzene cyclotrimers and a trans-cisoid polyene structure. (C) 2004 Wiley Periodicals, Inc.