We report on the synthesis of nearly monodisperse In2S3 nanoplatelets ∼7 nm thick by a low temperature polyol process using 1-thioglycerol as the capping chemical. The synthesized nanoplatelets crystallized in bulk tetragonal structure and show preferential crystallographic growth within a range of diameters from ∼75–85 nm. Quantum confinement was observed by spectroscopic analyses with a determined band gap of 3.4 eV. Strong UV luminescence corroborated valence-conduction band transition in these confined nanoplatelets. Room temperature photoconductance measurements performed on the prototype device fabricated from the nanoplatelets revealed noticeable enhancement of conductivity under illumination as compared to the dark condition.