A compound being capable of functioning as a phosphorescent emitter in an organic light emitting device at room temperature, wherein the compound has the formula of M(L 1) x (L 2) y (L 3) z; wherein L 1, L 2 and L 3 can be the same or different; wherein x is 1, 2, or 3; wherein y is 0, 1, or 2; wherein z is 0, 1, or 2; wherein x+y+z is the oxidation state of the metal M; wherein L 1, L 2 and L 3 are each independently selected from the group consisting of: wherein each X 1 to X 17 are independently selected from the group consisting of carbon and nitrogen; wherein X is selected from the group consisting of BR', NR', PR', O, S, Se, C=O, S=O, SO 2, CR'R", SiR'R", and GeR'R"; wherein R' and R" are optionally fused or joined to form a ring; wherein each R a, R b, R c, and R d may represent from mono substitution to the maximum possible number of substitution, or no substitution; wherein R', R", R a, R b, R c, and R d are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two or more substituents of R a, R b, R c, and R d are optionally fused or joined to form a ring or form a multidentate ligand; wherein at least one of the R a, R b, R c, and R d includes at least one substituent R; wherein each of the at least one substituent R has the formula of: ---G 1 -G 2; wherein the dashed line denotes the bond through which R is attached in the compound; wherein G 1 is a non-aromatic cyclic or polycyclic group; wherein G 2 is selected from aryl and heteroaryl; and wherein G 1 and G 2 are independently, optionally further substituted with a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. wherein each X 1 to X 17 are independently selected from the group consisting of carbon and nitrogen; wherein X is selected from the group consisting of BR', NR', PR', O, S, Se, C=O, S=O, SO 2, CR'R", SiR'R", and GeR'R"; wherein R' and R" are optionally fused or joined to form a ring; wherein each R a, R b, R c, and R d may represent from mono substitution to the maximum possible number of substitution, or no substitution; wherein R', R", R a, R b, R c, and R d are each independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; wherein any two or more substituents of R a, R b, R c, and R d are optionally fused or joined to form a ring or form a multidentate ligand; wherein at least one of the R a, R b, R c, and R d includes at least one substituent R; wherein each of the at least one substituent R has the formula of: ---G 1 -G 2; wherein the dashed line denotes the bond through which R is attached in the compound; wherein G 1 is a non-aromatic cyclic or polycyclic group; wherein G 2 is selected from aryl and heteroaryl; and wherein G 1 and G 2 are independently, optionally further substituted with a substituent selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.