A compound selected from the group consisting of Formula I wherein ring A and ring B are independently a five-membered or six-membered, carbocyclic or heterocyclic ring, each of which is optionally aromatic; ring W is a 6-membered heterocyclic ring; L is a monodentate ligand with a coordinating member N of the formula NR X R Y and is selected from the group consisting of: an optionally substituted carbazoyl, or an aza-derivative thereof; an optionally substituted diphenylamino, or an aza-derivative thereof; wherein R X', R Y', R N, R k and R 1 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, amino, silyl, aryl, heteroaryl, and combinations thereof; M is a metal selected from the group consisting of Cu, Au, and Ag; R A, R B, and R W represent mono to the maximum allowable substitution, or no substitution, and each R A, R B, and R C is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof, and R W is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof; or optionally, any two adjacent R A, R B, R C, or R W can join to form a ring, which is optionally substituted; and wherein the two R W do not join to form a naphthalene fused to ring W. ring A and ring B are independently a five-membered or six-membered, carbocyclic or heterocyclic ring, each of which is optionally aromatic; ring W is a 6-membered heterocyclic ring; L is a monodentate ligand with a coordinating member N of the formula NR X R Y and is selected from the group consisting of: an optionally substituted carbazoyl, or an aza-derivative thereof; an optionally substituted diphenylamino, or an aza-derivative thereof; wherein R X', R Y', R N, R k and R 1 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, amino, silyl, aryl, heteroaryl, and combinations thereof; M is a metal selected from the group consisting of Cu, Au, and Ag; R A, R B, and R W represent mono to the maximum allowable substitution, or no substitution, and each R A, R B, and R C is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof, and R W is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof; or optionally, any two adjacent R A, R B, R C, or R W can join to form a ring, which is optionally substituted; and wherein the two R W do not join to form a naphthalene fused to ring W. an optionally substituted carbazoyl, or an aza-derivative thereof; an optionally substituted diphenylamino, or an aza-derivative thereof; wherein R X', R Y', R N, R k and R 1 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, amino, silyl, aryl, heteroaryl, and combinations thereof; M is a metal selected from the group consisting of Cu, Au, and Ag; R A, R B, and R W represent mono to the maximum allowable substitution, or no substitution, and each R A, R B, and R C is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof, and R W is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof; or optionally, any two adjacent R A, R B, R C, or R W can join to form a ring, which is optionally substituted; and wherein the two R W do not join to form a naphthalene fused to ring W. wherein R X', R Y', R N, R k and R 1 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, amino, silyl, aryl, heteroaryl, and combinations thereof; M is a metal selected from the group consisting of Cu, Au, and Ag; R A, R B, and R W represent mono to the maximum allowable substitution, or no substitution, and each R A, R B, and R C is independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof, and R W is selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, and combinations thereof; or optionally, any two adjacent R A, R B, R C, or R W can join to form a ring, which is optionally substituted; and wherein the two R W do not join to form a naphthalene fused to ring W.