This contemporary work delineates the photocatalytic and antibacterial activity of titanium (Ti) and lanthanum (La)‐doped cadmium selenide (CdSe) nanoparticles produced by a simple wet chemical method. Studies using diffraction and microscopy reveal that the synthesized samples devised cubic crystalline structure. The incorporation of the dopant into the host material is analyzed using X‐ray diffraction, scanning electron microscope–EDAX, and transmission electron microscopic studies. The photocatalytic activity Ti‐ and La‐doped CdSe nanoparticles results in improved degradation toward methylene blue (MB) dye under direct solar irradiation. This unique behavior is ascribed to the enhanced light absorption tendency with larger charge separation efficiency. Ongoing operational factors like initial dye concentration, catalyst dose, pH, and duration are evaluated regarding their effects on MB dye degradation. The photocatalytic activity for MB follows pseudo‐first‐order kinetics. The antibacterial activity of Ti– and La–metal‐doped CdSe is tested against Pseudomonas arueginosa and Staph aureus bacteria. The Ti–CdSe and La–CdSe nanoparticles show good antibacterial activity after 24 h of bacterial growth Pseudomonas arueginosa and Staph aureus, respectively. Based on the findings, Ti–CdSe and La–CdSe nanoparticles exhibit an enhanced photocatalytic and antibacterial activity when compared with CdSe nanoparticles.