| 摘要 |
PROBLEM TO BE SOLVED: To obtain a luminescent material which emits a yellow to red light and has a high luminance and a long emission lifetime by using a monocyclic or condensed polycyclic compound having at least two specified substituents. SOLUTION: This material comprises a monocyclic or condensed polycyclic compound having at least two substituents represented by formula I. In formula I, R1 is a hydrogen atom, a substituted or unsubstituted alkyl, or a substituted or unsubstituted aryl; A is an oxygen atom or a methylene represented by formula II; B is an oxygen atom or a sulfur atom. In formula II, R2 and R3 are each independently a substituent selected from among a hydrogen atom, cyano, a halogen, an alkylcarbonyl, and an alkoxycarbonyl, provided that they can not be hydrogen atoms simultaneously and that R2 and R3 may be bonded with each other to form an integral group. The monocyclic or condensed polycyclic group is desirably one having at least two substituents represented by formula III (wherein R4 is R1 as defined in formula I).
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