An organic electroluminescence device includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region, the emission layer including a polycyclic compound, an electron transport region on the emission layer, and a second electrode on the electron transport region, wherein the polycyclic compound includes an isophthalonitrile derivative, a linker, and a nitrogen-containing group, the linker is a condensed cyclic group of three rings that are independently five-membered or six-membered rings, and each of the isophthalonitrile derivative and the nitrogen-containing group is substituted into a same ring of the linker.