A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission part disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer disposed on the first emission layer, the first emission layer may include a first host, and a first dopant, and the second emission layer may include a hole transport host different from the first host, an electron transport host, and a second dopant. A first hole mobility of the first host may be in a range of about 5.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−3 cm.sup.2/Vs, a second hole mobility of a host mixture including the hole transport host and the electron transport host may be in a range of about 1.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−4 cm.sup.2/Vs, and the first hole mobility may be larger than the second hole mobility.

A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission part disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer disposed on the first emission layer, the first emission layer may include a first host, and a first dopant, and the second emission layer may include a hole transport host different from the first host, an electron transport host, and a second dopant. A first hole mobility of the first host may be in a range of about 5.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−3 cm.sup.2/Vs, a second hole mobility of a host mixture including the hole transport host and the electron transport host may be in a range of about 1.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−4 cm.sup.2/Vs, and the first hole mobility may be larger than the second hole mobility.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A chemical reaction is catalyzed in an organic solvent using a water soluble N-heterocyclic carbene homogeneous catalyst to form a reaction mixture. An aqueous phase in the reaction mixture. A solvent in which the catalyst is insoluble is added to the reaction mixture, causing the catalyst to migrate to the aqueous phase to form a catalyst-laden aqueous phase. The catalyst is extracted from the catalyst-laden aqueous phase.

A chemical reaction is catalyzed in an organic solvent using a water soluble N-heterocyclic carbene homogeneous catalyst to form a reaction mixture. An aqueous phase in the reaction mixture. A solvent in which the catalyst is insoluble is added to the reaction mixture, causing the catalyst to migrate to the aqueous phase to form a catalyst-laden aqueous phase. The catalyst is extracted from the catalyst-laden aqueous phase.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A method for separating a homogeneous catalyst from a solution includes forming a host-guest compound between a first isomer of the catalyst and inclusion compound in the solution and isolating the host-guest compound from the solution. The catalyst may be released from the inclusion compound by converting the first isomer of the catalyst to a second isomer of the catalyst.

A condensed cyclic compound represented by Formula 1:

##STR00001## wherein, in Formula 1, groups and variables are the same as described in the specification.

A condensed cyclic compound represented by Formula 1:

##STR00001## wherein, in Formula 1, groups and variables are the same as described in the specification.