TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Compound (I) is prepared by performing Suzuki reaction to bromo-containing fluoreneporphyrin derivative of formula (II) and thienopyrazine derivatives of formula (III) for 24-72 hours at 50-120 degrees C in the presence of catalyst and organic solvent, and in free-oxygen condition to obtain porphyrin compound (I). Preferred Method: Compound (II) is prepared by dissolving dipyrrylmethane, aldehyde of formula (IV) and fluorene derivatives of formula (V) in organic solvent under anhydrous and anaerobic conditions; reacting for 1-24 hours at 20-100 degrees C under catalytic condition; regulating temperature of reaction system at 10-40 degrees C; adding catalyst; reacting for 1-100 minutes to obtain fluorene porphyrin derivative of formula (VI); dissolving compound (VI) in organic solvent under anhydrous and anaerobic conditions; adding brominating agent and alkali; and reacting for 1-72 hours at 0-120 degrees C to obtain compound (II). Compound (III) is prepared by dissolving 5,7-dibromothieno(3,4-b) pyrazine in organic solvent under anaerobic condition; adding alkyl lithium at - 100 to - 25 degrees C; keeping temperature and adding bis(pinacolato) diboron; reacting mixture for 0.5-5 hours; regulating temperature at 10-40 degrees C; and reacting for 5-48 hours to obtain compound (III). Preferred Component: The mol ratio of compound (II) to compound (III) is (1:5)-(5:1), and molar weight of catalyst is 0.05-20% that of compound (III). The mol ratio of sum of compound (IV) and compound (V) is to dipyrrylmethane is 1:1.0. The molar weight of catalyst is 1-30 times that of dipyrrylmethane in preparation method of compound (VI). The mol ratio of catalyst is 1-10 times of molar weight of dipyrrylmethane in brominating reaction. The mol ratio of compound (VI) to brominating agent is 1:(2-5). The molar weight of alkali is 1-50 times that of brominating agent. The mol ratio of 5,7-dibromo-thieno(3,4-b) pyrazine to alkyl lithium is 1:(2-5). The molar weight of bis(pinacolato)diboron is 5-10 times that of 5,7-dibromo-thieno(3,4-b) pyrazine. Preferred Definitions:    R1-R4=8-32C alkyls.