Cu2SnS3 (CTS) quantum dots were synthesized by solvothermal technique with poly(vinylpyrrolidone) (PVP) as a surfactant. The structural and optical properties were studied using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. The electronic band gap was measured using cyclic voltammetry. The infrared photoresponse of the CTS quantum dots incorporated device was measured under different illumination intensities of the infrared lamp, 1550 and 1064 nm lasers. The characteristics of the photodetector device, that is, responsivity, external quantum efficiency, and specific detectivity were calculated. This study proves the potential use of CTS quantum dots in infrared photodetectors.