Organic electroluminescent element, display device, illumination device, and pi-conjugated compound

An organic electroluminescent element comprising an anode, a cathode, and an organic layer including a light-emitting layer sandwiched between the anode and the cathode, wherein the light-emitting layer comprises:

• at least one luminescent compound selected from a fluorescence-emitting compound;
• a host;
• and
• an assist dopant, wherein the assist dopant is selected from π-conjugated compounds having a structure represented by any of the following General Formulas 2 to 3:
• wherein Xs each independently represent O, and R5 to R16 each independently represent a hydrogen atom or a substituent;
• provided that at least one of R5 to R16 or at least one of R9 to R16 represents a group represented by the following General Formula 4:
• wherein Ar1 and Ar2 each independently represent a substituted or unsubstituted aryl group, L1 represents a single bond or a substituted or unsubstituted arylene group, and # represents a bonding to the General Formulas 2 to 3;
• and Ar1 and Ar2 may form a ring structure via a single bond or a crosslinking group,
• wherein energy levels S1 and T1 of the assist dopant are lower than energy levels S1 and T1 of the host compound and higher than energy level S1 of the luminescent compound, and
• wherein an amount of the fluorescence-emitting compound is 0.1 to 50% by mass ratio relative to the assist dopant.