A polycyclic compound represented by the following Formula 1: in Formula 1, Y is B, P=O, or P=S, each of R 1 and R 2 is independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amine group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, a substituted or unsubstituted phosphine group, a substituted or unsubstituted phosphine oxide group, a substituted or unsubstituted phosphine sulfide group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or may be combined with an adjacent group to form a hydrocarbon ring or a heterocycle, at least one of R 1 or R 2 is represented by the following Formula 2: in Formula 2, Z is a direct linkage, O, S, Se, NAr 11, POAr 12, CAr 14 Ar 15, SiAr 16 Ar 17, GeAr 18 Ar 19, or BAr 20, n is 0 or 1, each of Ar 11 to Ar 12 and Ar 14 to Ar 20 is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or may be combined with an adjacent group to form a hydrocarbon ring or a heterocycle, R 7 is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, and "c" is an integer between 0 and 8, inclusive, Ar 1 is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, X is SiR 3 R 4, or GeR 5 R 6, each of R 3 to R 6 is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, "a" is an integer between 0 and 8, inclusive, "b" is an integer between 0 and 5, inclusive, a+b≠0, if R 1 is Formula 2, "a" is an integer between 1 and 8, inclusive, and if R 2 is Formula 2, "b" is an integer between 1 and 5, inclusive. Y is B, P=O, or P=S, each of R 1 and R 2 is independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amine group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, a substituted or unsubstituted phosphine group, a substituted or unsubstituted phosphine oxide group, a substituted or unsubstituted phosphine sulfide group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or may be combined with an adjacent group to form a hydrocarbon ring or a heterocycle, at least one of R 1 or R 2 is represented by the following Formula 2: Z is a direct linkage, O, S, Se, NAr 11, POAr 12, CAr 14 Ar 15, SiAr 16 Ar 17, GeAr 18 Ar 19, or BAr 20, n is 0 or 1, each of Ar 11 to Ar 12 and Ar 14 to Ar 20 is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, or may be combined with an adjacent group to form a hydrocarbon ring or a heterocycle, R 7 is a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, and "c" is an integer between 0 and 8, inclusive, Ar 1 is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, X is SiR 3 R 4, or GeR 5 R 6, each of R 3 to R 6 is independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms for forming a ring, "a" is an integer between 0 and 8, inclusive, "b" is an integer between 0 and 5, inclusive, a+b≠0, if R 1 is Formula 2, "a" is an integer between 1 and 8, inclusive, and if R 2 is Formula 2, "b" is an integer between 1 and 5, inclusive.