An organic compound comprising a complex fluorene structure represented by the following Formula: ##STR00001## wherein: X.sub.1, X.sub.2, X.sub.3, and X.sub.4 include carbon atoms and at least one nitrogen atom; R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are substituents each being individually hydrogen, or amino, or alkyl, or alkenyl, or alkynyl, or alkoxy of from 1 to 40 carbon atoms; aryl or substituted aryl of from 6 to 60 carbon atoms; or heteroaryl or substituted heteroaryl of from 4 to 60 carbons; or F, Cl, or Br; or a cyano group; or a nitro group; or R.sub.3, or R.sub.4 or both are groups that form fused aromatic or heteroaromatic rings; or R.sub.1 and R.sub.2 together form a cyclic ring having 3 to 20 carbon, nitrogen, sulfur or oxygen atoms; or R.sub.1 and R.sub.2 together form a double bond moiety.