A composition including a first compound capable of functioning as a phosphorescent emitter in an OLED is provided. The first compound has at least one aromatic ring and at least one substituent R directly bonded to one of the at least one aromatic rings. Each substituent R has the formula of where (a) G1 is selected from NR1, SiR1R2, GeR1R2, alkyl, cycloalkyl, and combinations thereof; and G2 is a non-aromatic polycyclic group; (b) G1 is a direct bond; and G2 is a non-aromatic spiro polycyclic group; or (c) G1 is selected from direct bond, NR1, SiR1R2, GeR1R2, alkyl, cycloalkyl, and combinations thereof; G2 is a non-aromatic polycyclic group; and R is directly bonded to a phenyl, pyridine, or triazine. R1, R2, and R3 are a variety of substituents. Formulations and devices, such as an OLEDs, that include the first compound are also described.