Polymer, composition including the polymer, and organic light-emitting device including the polymer

A polymer comprising a first repeating unit represented by Formula 1 and a second repeating unit represented by Formula 2:

• wherein, in Formulae 1, 2, and 9,
• Z11 is selected from N and C(R11), Z12 is selected from N and C(R12), Z13 is selected from N and C(R13), Z14 is selected from N and C(R14), Z15 is selected from N and C(R15), Z16 is selected from N and C(R16), Z17 is selected from N and C(R17), and Z18 is selected from N and C(R18),
• Ar11 and Ar21 are each independently selected from a substituted or unsubstituted C5-C30 carbocyclic group and a substituted or unsubstituted C1-C30 heterocyclic group,
• L11 to L13, L21 to L23, and L91 to L93 are each independently selected from a single bond, a substituted or unsubstituted C1-C24 alkylene group, a substituted or unsubstituted C6-C30 arylene group, a substituted or unsubstituted C1-C30 heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,
• a11 to al 3, a21 to a23, and a91 to a93 are each independently selected from 0, 1, 2, and 3,
• R11 to R18 are each independently selected from a group represented by Formula 9, hydrogen, a substituted or unsubstituted C1-C24 alkyl group, a substituted or unsubstituted C1-C24 alkoxy group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C1-C30 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, wherein at least one of R11 to R18 is a group represented by Formula 9, and two neighboring groups selected from R11 to R18 are optionally linked to form a ring,
• R91 and R92 are each independently selected from a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C1-C30 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group,
• Q21 is a crosslinking group,
• o21 is an integer greater than or equal to 1,
• p21 is an integer greater than or equal to 1, and
• * and *′ each indicate a binding site to a neighboring atom.