A selenophene-containing conjugated organic ligand, 2-(4′-methyl-5′-(5-(3-methylthiophen-2-yl)selenophen-2-yl)-[2,2′-bithiophen]-5-yl)ethan-1-aminium (STm), was synthesized and incorporated into a Sn(II)-based two-dimensional perovskite, (STm)₂SnI₄. The band offset between the perovskite and ligand can be fine-tuned by introducing the STm ligand. Both field-effect transistor and light-emitting diode devices based on (STm)₂SnI₄ films exhibit high performance and enhanced operational stability.