wherein

Z³ is selected from the group consisting of O, S, N—R₆, or P—R₆, wherein R₆ is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aralkyl, O—R′, N(R′)₂, SR′, C(O)R′, C(O)OR′, C(O)NR′₂, CN, CF₃, NO₂, SO₂, SOR′, SO₃R′, halo, and heteroaryl; each R′ is independently selected from H, alkyl, alkenyl, alkynyl, heteroalkyl, aralkyl, aryl, and heteroaryl; and

A is independently selected from C, N, O, P, or S;

(X—Y) is a bidentate photoactive ligand or a bidentate ancillary ligand;

ring B is independently an aromatic cyclic, heterocyclic, fused cyclic, or fused heterocyclic ring, wherein ring B can be optionally substituted with one or more substituents R¹⁴; and

ring D is independently a cyclic, heterocyclic, fused cyclic, or fused heterocyclic ring with at least one carbon atom coordinated to metal M, wherein ring D can be optionally substituted with one or more substituents R¹⁵; and

R¹⁴ and R¹⁵ are independently selected from alkyl, alkenyl, alkynyl, aralkyl, R′, O—R′, N(R′)₂, SR′, C(O)R′, C(O)OR′, C(O)NR′₂, CN, CF₃, NO₂, SO₂, SOR′, SO₃R′, halo, aryl, and heteroaryl; each R′ is independently selected from H, alkyl, alkenyl, alkynyl, heteroalkyl, aralkyl, aryl, and heteroaryl; or

alternatively, two R¹⁴ groups on adjacent ring atoms and R¹⁵ groups on adjacent ring atoms form a fused 5- or 6-membered cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl or heteroaryl; and wherein said cyclic group is optionally substituted by one or more substituents J;

b is 0, 1, 2, 3, or 4;

e is 0, 1, 2, or 3;

m has a value from 1 to the maximum number of ligands that may be attached to the metal; and m+n is the maximum number of ligands that may be attached to metal M.