2,3-Bis(5-bromo-2-thien­yl)-6,7-dichloro­quinoxaline

The title compound, C₁₆H₆Br₂Cl₂N₂S₂, was synthesized from the reaction of equimolar amounts of 1,2-diamino-4,5-dichloro­benzene and 1,2-bis­(5-bromo­thien-2­yl)ethanedione. The crystal structure was determined at 100 K.

5-Nitro­thio­phene-2-carb­aldehyde

In the crystal structure of the title compound, C₅H₃NO₃S, determined at 100 K, the nitro group and the aldehyde group make angles of 8.37 (16) and 8.5 (4)°, respectively, with the plane of the thio­phene ring.

N,N'-Bis(9H-fluoren-9-yl­idene)benzene-1,2-diamine

The title compound, C₃₂H₂₀N₂, was synthesized by the p-toluene­sulfonic acid-assisted Schiff base reaction between 9-fluorenone and o-phenyl­enediamine. The mol­ecule crystallizes in a centrosymmetric space group and is located on a twofold rotation axis. The two fluoren-9-yl­idene moieties adopt a trans configuration as substituents on the linking benzene ring, making the entire mol­ecule chiral.

1,2-Bis(3-methyl-2-thien­yl)ethane-1,2-dione

The molecule of the title compound, C₁₂H₁₀O₂S₂, is disposed about a centre of inversion and is essentially planar.

2-(2-Thien­yl)quinoxaline

The crystal structure of the title compound, C₁₂H₈N₂S, was determined at 293 K. The mol­ecule is planar and packs in a herring-bone pattern.