Copper zinc tin sulphide (CZTS) has emerged as a highly promising, cost-effective, and environmentally friendly material for solar energy conversion via photovoltaic and photocatalysis. This paper presents the synthesis of quasi Cu2ZnSnS4 nanoparticles using a hydrothermal route with citric acid as a structure-directing agent. The CZTS nanoparticles' morphological, structural, and optical properties were comprehensively analysed using X-ray diffraction, scanning electron microscopy, and UV-Vis absorption studies. The results demonstrate the successful synthesis of CZTS nanoparticles with a novel narrow size distribution, making them excellent candidates as absorber layers in solar cells. This discovery holds significant potential for advancing low-cost and efficient solar energy conversion technologies. By harnessing the unique properties of CZTS, this research offers a promising solution towards sustainable energy production and a greener future.