Electronic characterization of mono-keto-mono-thioketo-pyrrolopyrrole (MTPP) has been carried out in order to explore new electronic applications. The crystal structure of MTPP is found to be isomorphous with that of modification I of dithioketopyrrolopyrrole (DTPP). The color is nearly between those of diketopyrrolopyrrole (DPP) and DTPP. The intermolecular hydrogen bonds based on both NH…O and NH…S are found to be considerably weak as compared with those of DPP (NH…O) and DTPP (NH…S). The absorption spectrum of MTPP suggests a potential application for LCD blue-filters.