The photoluminescence (PL) and the electroluminescence (EL) behaviors of six derivatives of the pyrazoline dimer and monomer have been studied. It was found that the pyrazoline compounds with an aryl group attached to the 5-position of the pyrazoline ring have better film-forming property. Dimerization of the pyrazoline derivatives can improve the film-forming property while decrease the fluorescence yield. When these compounds were used in EL devices as fluorescence dopants in an N-arylbenzimidazoles trimer (TPBI), high efficiency EL was observed.