2 anthryl group a 9 anthryl group a 9 anthryl d9 group a 2 phenanthryl group a 3 phenanthryl group a 4 phenanthryl group a 9 phenanthryl group a 9 phenanthryl d9 group a 1 pyrenyl group a 1 pyrenyl d9 group a 2 pyrenyl group a 4 pyrenyl group a tetracenyl group a pentacenyl group a fluorenyl group a triphenylenyl group and a perylenyl group examples of a substituted or unsubstituted heterocyclic group include but are not limited to a pyrrolyl group a pyridyl group a pyridyl d5 group a bipyridyl group a methylpyridyl group a terpyrrolyl group a thienyl group a thienyl d4 group a terthienyl group a propylthienyl group a furyl group a furyl d4 group an indolyl group a 1 10 phenanthroline group a phenazinyl group a quinolyl group a carbazolyl group an oxazolyl group an oxadiazolyl group a thiazolyl group and a thiadiazolyl group examples of a substituted or unsubstituted alkylene group include but are not limited to a methylene group a methylene d2 group a difluoromethylene group an ethylene group an ethylene d4 group a perfluoroethylene group a propylene group an iso propylene group a butylene group and a 2 2 dimethylpropylene group examples of a substituted or unsubstituted aralkylene group include but are not limited to a benzylene group a 2 phenylethylene group a 2 phenylisopropylene group a 1 naphthylmethylene group a 2 naphthylmethylene group a 9 anthrylmethylene group a 2 fluorobenzylene group a 3 fluorobenzylene group a 4 fluorobenzylene group a 4 chlorobenzyl group and a 4 bromobenyzlene group examples of a substituted or unsubstituted alkenyl group include but are not limited to a vinylene group an iso propenyl group a styrylene group and a 1.