TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Dialkynyl-containing compound of formula (1) is reacted with a reducing agent and further with an electrophilic reagent to obtain the indacene derivative. Preferred Properties: The indacene derivative has light emission wavelength of 380-700 nm, luminous efficiency of 0.10 or more, and hole mobility and electron mobility of more than 1x 10-5 cm2.V-1.second-1, respectively. Preferred Compound: The electrophilic reagent is carbonyl compound, imine compound, organo silicon compound, organo tin compound or organo boron compound. Preferred Definitions:    R1,R2=methyl, ethyl or phenyl;and    Ar1-Ar6=optionally substituted phenyl.    SPECIFIC COMPOUNDS - 5 Indacene derivatives are disclosed, e.g. 5,10-dihydro-5,5,10,10-tetraphenyl indino(2,1-a)indene of formula (A), (5-(hydroxy-diphenyl-methyl)-2,3,3,6,7,7-hexaphenyl-3,7-dihydro-s-indacen-1-yl)-diphenyl-methanol, 1,1,2,5,5,6-hexaphenyl-1,5-dihydro-s-indacene, diiodo-1,1,2,5,5,6-hexaphenyl-1,5-dihydro-s-indacene and 1,1,2,3,5,5,6,7-octaphenyl-1,5-dihydro-s-indacene.    EXAMPLE - (In g) n-butyl lithium/n-hexane (20 ml) was added to ethyl ether solution (60 ml) of 1-bromo-2-(phenyl ethynyl)benzene (7.71). Diphenyl ketone (5.47) was further added and the contents were stirred at room temperature for 1 hour. The reaction mixture was filtered after adding ammonium chloride aqueous solution and the crude product was recrsytallized with ethyl acetate to obtain 1-phenyl ethynyl-2-diphenylhydroxy methyl benzene (6.33) with yield of 59%. Liquid mixture containing granular lithium (6.7 mg) in tetrahydrofuran and naphthalene (102 mg) was added to tetrahydrofuran solution of the obtained compound (150). Tetrahydrofuran solution of naphthyl lithium was added and the contents were stirred for 15 minutes after adding ammonium chloride aqueous solution. The obtained mixture was filtered and purified to obtain diphenyl(1,1,2-triphenyl-1H-inden-3-yl)methanol (204 mg) with yield of 97%. The obtained compound was reacted with boron trifluoride in presence of diethyl ether and chloroform at room temperature to obtain 5,10-dihydro-5,5,10,10-tetraphenyl indino(2,1-a)indene (96 mg) with yield of 94%.