It has a "rotten egg" odor characteristic of sulfur compounds, and produces hydrogen sulfide gas when reacted with mineral acids.

It has been proposed to replace the hazardous cadmium sulfide, CdS, as a buffer layer in solar cells,[8] and as an additional semiconductor to increase the performance of TiO2-based photovoltaics.

Production from volatile complexes of indium and sulfur, for example dithiocarbamates (e.g. Et2InIIIS2CNEt2), has been explored for vapor deposition techniques.

Solutions of In(III) salts and organic sulfur compounds (often thiourea) are sprayed onto preheated glass plates, where the chemicals react to form thin films of indium sulfide.

[10] Changing the temperature at which the chemicals are deposited and the In:S ratio can affect the optical band gap of the film.

[11][14] Thin films β-In2S3 can be grown with varying band gaps, which make them widely applicable as photovoltaic semiconductors, especially in heterojunction solar cells.

[15] A preparation of indium sulfide made with the radioactive 113In can be used as a lung scanning agent for medical imaging.

Preparing In2S3 nanoparticles in the presence of other heavy metal ions creates highly efficient blue, green, and red phosphors, which can be used in projectors and instrument displays.