TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The toluene is added to the reaction system, and extracted using deionized water, to obtain organic phase. The organic phase is removed using vacuum distillation, organic phase is dropped into anhydrous methanol to precipitate, filtered and dried, to obtain solid powder. The obtained solid powder is dissolved using chloroform, catalyst is removed using chromatographic column, and chloroform is removed. The fluorene derivative (II) is obtained by injecting fluorene compound of formula (IV) into tetrahydrofuran solvent, slowly adding n-butyl lithium at -70 degrees C to -85 degrees C, stirring reaction solution for 0.5-4 hours, slowly injecting with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-oxopentyl borane at -70 degrees C to -85 degrees C, raising the temperature to room temperature for 10-48 hours, separating and purifying. A saturated sodium chloride solution is added and extracted using chloroform, dried using anhydrous sodium sulfate or anhydrous magnesium sulfate, and filtered. The filtrate is collected, and solvent is removed, to obtain crude product. The crude product is eluted using dichloromethane by silica gel column chromatography, to obtain fluorene derivative (II). 9-(Bis-methylsulfanyl-methylene)-9H-fluorene is dissolved in a tetrahydrofuran solvent with continuous stirring at -5 degrees C under the protection of hydrogen, diethyl ether solution of formula: R1MgBr is added, maintained at 0 degrees C for 30 minutes. The reaction solution is neutralized using sodium hydroxide solution for 10-20 minutes and purified, to obtain compound (IV). 2,7-Dibromo-fluorene and potassium tert-butoxide are added into anhydrous dimethylsulfoxide under protection of nitrogen, then carbon disulfide is added into the reaction solution, stirred for 10-20 minutes and purified, to obtain 9-(bis-methylsulfanyl-methylene)-9H-fluorene. Preferred Composition: The molar ratio of n-butyl lithium and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-oxydioxaborolan is 1:1-2. The molar ratio of fluorene compound (IV) and n-butyl lithium is 1:2-4. The molar ratio of compound D and diethyl ether solution is 1:2-2.4. The molar ratio of 2,7-dibromofluorene and potassium tert-butoxide is 1:2-2.4. The molar ratio of 2,7-dibromofluorene and carbon disulfide is 1:1-1.2. The molar ratio of 2,7-dibromofluorene and iodomethane is 1:1-1:1.2.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): A fluorene derivative of formula (II) and nitrogen-containing compound of formula (III) are reacted with sodium carbonate aqueous solution in the molar ratio of 1:1:0.005-0.05, then toluene is added as solvent under reflux at 60-100 degrees C for 24-72 hours, and separated and purified, to obtain alkylene fluorene-containing organic polymer (I).