An organic electro-luminescent element having a luminescence peak in a near-infrared range, comprising a positive electrode, a negative electrode, and at least one organic layer including a luminescent layer located between the positive electrode and the negative electrode, wherein the luminescent layer comprises a host material, a delayed fluorescent material and a luminescent material, wherein each of the delayed fluorescent material and the luminescent material have a structure with two or three benzene rings bonded to an N atom.

Hydrophilic, chemiluminescent acridinium compounds containing zwitterions are disclosed. These acridinium compounds, when used as chemiluminescent labels in immunochemistry assays and the like, exhibit decreased non-specific binding to solid phases and provide increased assay sensitivity.

Hydrophilic, chemiluminescent acridinium compounds containing zwitterions are disclosed. These acridinium compounds, when used as chemiluminescent labels in immunochemistry assays and the like, exhibit decreased non-specific binding to solid phases and provide increased assay sensitivity.

A compound represented by formula [I]:

##STR00001##

wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, or C.sub.1-6 alkoxy optionally substituted with halogen; R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; R.sup.3 is C.sub.1-6 alkyl or the like; and X.sup. is an anion.

A compound represented by formula [I]:

##STR00001##

wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, or C.sub.1-6 alkoxy optionally substituted with halogen; R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; R.sup.3 is C.sub.1-6 alkyl or the like; and X.sup. is an anion.