This invention relates to a borane derivative represented by the formula (1) and an organic electroluminescent device: wherein R1 to R8 and Z2 are each independently a hydrogen atom, a saturated or unsaturated hydrocarbon group, an aromatic group, a heterocyclic group, a substituted amino group, a substituted boryl group, an alkoxy group or an aryloxy group; X, Y and Z1 are each independently a saturated or unsaturated hydrocarbon group, an aromatic group, a heterocyclic group, a substituted amino group, an alkoxy group or an aryloxy group; substituents of Z1 and Z2 may be united to form a condensed ring; and n is an integer of 1-3; with the provisos that when n is two or more, Z1s may be different from each other; and that cases where n is 1, X, Y and R2 are each methyl, and R8 is hydrogen or substituted boryl and those where n is 3 and Z1 is methyl are excluded. The borane derivatives of this invention are suitable for luminescent materials by virtue of their high luminous efficiencies in solid states, and useful for electrophotography and as photoelectronic functional materials including nonlinear optical materials and conductive materials. The use of this borane derivative brings about an organic EL device characterized by low electricity consumption and high efficiency.