This dataset contains underlying data of publication entitled "Synthesis and physical characteristics of narrow bandgap chalcogenide SnZrSe3". Data comprises: -Sample description.txt (synthesis conditions of the sample presented in the publication) -F1IS_V_6244.cif (crystallographic information file about SnZrSe3 structure as determined by single-crystal XRD method). - XRD.zip (raw XRD patterns of powder samples presented in the publication in .ras and .raw formats). -Raman.zip (raw Raman spectra in .txt format and OriginPro project file where data was processed and plotted). -Optics.zip (raw diffuse reflectance data in .txt format and OriginPro project file where data was processed and plotted). -JV-T.zip (J-V curves at specific temperature in .txt format and OriginPro project files where data was processed and plotted). -Images.zip (optical photographs of the sample and untreated SEM images of SnZrSe3 crystals). -Extented data.pdf (additional information supporting claims in the publication with direct link to the main text, such as figures).