This work for the first time develops and employs the novel cerium‐praseodymium‐neodymium oxide co‐doped tin oxide (Ln3+(Ce3+‐Pr3+‐Nd3+):SnO2) system for varied energy applications including electro‐catalytic, super‐capacitive, and photovoltaic conversion potential. The outstanding optical, compositional, crystalline, and morphological aspects of the synthesized material express its effectiveness for energy related micro‐electrochemical applications. Bandgap narrowing due to lanthanide doping and acquiring cassiterite crystalline phase results in the auspicious output. O2 and H2 evolution of the developed electro‐catalyst expresses superior energy production with lower overpotential values of 95 mV for O2 and 131 mV toward H2. Fabricated electrode expresses an impressive charge storage potential with the specific capacitance of 151.62 F g−1. Also, this electrode has an extended service life for 100 min showing its ultra‐durability for commercial applications. Ln3+(Ce3+‐Pr3+‐Nd3+):SnO2 is used as an electron transport layer in the cesium based solar cells with the power conversion efficiency of 12.49%, short circuit current of 19.63 mA cm−1, and open circuit voltage of 1.2 V under artificial sun with negligible hysteresis. Ln3+(Ce3+‐Pr3+‐Nd3+):SnO2 is an effective material with the perfect bandgap tuned exceeding the pristine material for diverse energy applications marked by profound sustainability and economic viability.