“…The interest stems from the fact that these species are thought to be stabilized by van der Waals forces, , rather than by exciton resonance (which stabilizes singlet excimer), and hence are expected to have structures and properties that are substantially different from those of the corresponding singlet excimers. , However, because of the difficulty of distinguishing excimer phosphorescence from the impurity emission (sensitized by energy transfer from the triplet state of the compound), it has proven to be problematic to identify and characterize aromatic triplet excimers in fluid solutions. , Nonetheless, time-resolved absorption and emission studies on a number of systems provide strong evidence for the formation of triplet excimers with spectra that are distinctly different from those of the corresponding triplet monomers. The molecular systems reported to exhibit intramolecular triplet excimer formation in fluid solutions are dinaphthylalkanes, , dicarbazolylakanes, dinaphthyl ether, dinaphthylamine, naphthalene end-labeled poly(ethylene)glycol, phosphazine polymers with pendant naphthalenes, quinoxaline-annelated dimer, diphenanthrylpropane, and bis[1-(1-pyrenyl)ethyl]ether . Intermolecular triplet excimer formation in fluid solutions has been reported for carbazole, N -ethylcarbazole, dibenzofuran, dibenzothiophene, , naphthalene (for which there have been disputes ,, ), and for the neat liquid of 1-methylnaphthalene and 1-chloronaphthalene …”