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Various dipyrroles possess important motifs for construction of pyrrole-containing pigments. A series of 1,2-dipyrrolylethynes (4a–d) has been efficiently synthesized using an improved one-pot double Sonagashira coupling from trimethylsilylethyne and various 2-iodopyrroles. The resulting 1,2-dipyrrolylethynes were further transformed into novel indolyl-, ethenyl- and carboranyl-dipyrroles (5–7) using the Larock indole synthesis, stereoselective catalytic hydrogenation, or B10H14. Indolyl-dipyrroles were found to selectively bind fluoride ions using one pyrrolic and the indolyl NHs, whereas the carboranyl- and ethenyl-dipyrroles are potentially valuable precursors for the synthesis of porphyrin isomers and expanded pigments.

The title mol­ecule, C30H28N2O4, has crystallographic twofold rotation symmetry, with the pyrrole planes forming a dihedral angle of 40.49 (4)°. The pyrrole N—H donor and adjacent ester carbonyl acceptor form R 2 2(10) hydrogen-bonded rings about inversion centers, leading to chains of hydrogen-bonded mol­ecules along [001].

The title mol­ecule, C24H20N2O4S2, has crystallographic inversion symmetry with a triple-bond distance of 1.206 (2) Å. The alkyne is not quite linear, with a C—C C angle of 175.78 (16)°. The planar pyrrole rings are parallel but offset from coplanarity by 0.318 (1) Å. The conformation of the sulfonyl group with respect to the pyrrole ring is such that an O atom is nearly eclipsed with this ring, having an O—S—N—C torsion angle of 3.48 (11)°. C—H⋯O inter­actions [C⋯O 3.278 (2) Å, 136° about H] between pyrrole H and sulfonyl O atoms lead to the formation of ladder-like chains.

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