Abstract Cadmium selenide (CdSe) nanoparticles were synthesized in aqueous medium using mercaptopropionic acid (MPA) as the stabilizer at the temperature 100 °C. Air stable sodium selenite (Na2SeO3) was used as the selenium source. The synthesized particles were used to co-sensitize the TiO2 nanotubes with N3 dye. Ex-situ linker assisted method was used to sensitize the nanotubes by CdSe nanoparticles. Electrochemical anodization technique was employed to prepare TiO2 nanotubes in the presence of hydrogen fluoride (HF) as electrolyte. A solar cell was fabricated using co-sensitized TiO2 nanotubes by N3 dye/CdSe nanoparticles as the anode and platinum coated fluorine doped tin oxide (FTO) electrode as the cathode. Polysulphide ( S 2 - / S x 2 - ) mixture was used as the electrolyte. UV–Visible, SEM, AFM and TEM analysis were used to characterize the synthesized particles and TiO2 nanotubes.