[en] Highlights: • Nanowalls CdS/dye sensitized solar cells are fabricated. • Some physical properties are investigated. • CdS/Eosin methylene blue device gives the highest conversion efficiency of 0.89%. • Heat treatment of the solar cells produces significant enhancement in the output. A microwave assisted chemical bath deposition (MA-CBD) was adopted to fabricate nanowalls CdS nanocrystalline thin film. Nanomaterials (such as nanowalls structure) have attracted significant attention due to their fascinating properties and unique applications, especially in optoelectronic nanodevices. Here we describe the fabrication of dye sensitized solar cells (DSSCs) based nanowalls cadmium sulfide (CdS) nanocrystalline thin films. The surface morphology, crystalline structure, and optical properties of the prepared nanocrystalline thin films are investigated. Rhodamine B, Malachite green, Eosin methylene blue, and Cresyl violet perchlorate dyes are used to fabricate the DSSC_S devices. Current-voltage (I-V) characteristics show that the nanowall CdS/Eosin methylene blue device is the highest conversion efficiency of 0.89% under 100 mW/cm². However, heat treatment of the fabricated solar cells causes significant enhancement in the output of all devices.