Tetracoordinate silicon complexes of 1,2-bis(indol-2-yl)benzene as blue-emitting dyes in the solid state.

1,2-Bis(indol-2-yl)benzene was prepared and found to serve as an effective bidentate ligand to form stable silicon complexes bearing two N-Si bonds. These complexes take boat-shaped 2,7-diaza-1-silepin structures, which undergo a butterfly-like conformational motion whose activation barriers were determined by shape analysis of variable-temperature (1)H NMR spectra. These silicon complexes exhibit blue emissions in solution and in the solid-state with high efficiency.