Pyrrolopyrroles (DPP) are industrially important red pigments in paint and imaging areas. The title compound is a soluble precursor of DPP called mono-BOC DPP (“latent pigment”), in which one of the NH groups in DPP is replaced by a t-butoxycarbonyl (t-BOC) group to make it soluble in organic solvents. The regeneration and regenerated product of mono-BOC DPP have been studied in terms of thermogravimetric and X-ray diffraction analyses, as well as IR and diffuse reflectance spectra on powdered substances. Transformation from mono-BOC DPP to the parent DPP begins around 170°C and is completed around 220°C, accompanied by evolution of CO₂. The crystal phase of thermally regenerated DPP is different from that of DPP, although the diffuse reflectance spectrum of regenerated DPP on powder is quite similar to that of commercial one.