TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): Preparation of (I) comprises: bromination of a 1-phenylbenzoindole compound of formula (Z) using a N-bromosuccinimide at -20 degrees C to 0 degrees C to give a 4-bromo-phenylbenzoindole compound (Z1); mixing (Z1) with a thiophene compound of formula (Z2), tetrakis(triphenylphosphine)palladium and lithium chloride to give a thiophene group-containing compound (Z3); reacting (Z3) with a fluorene-based compound of formula (Z4) to give a N-fluorene substituted benzoindole compounds of formula (Z5); introducing an aldehyde group using an alkyl lithium, such as n-butyl lithium, at -78 degrees C to -40 degrees C in the presence of trifluoroacetic acid at 0-25 degrees C to give a bithiophenyl-5-carbaldehyde substituted benzoindole compounds of formula (Z6); and reacting (Z6) with a cyanoacetic acid, piperidine and acetonitrile to give a benzoindole-based compound of formula (Ib) (representative compound of (I)).R1, R2 = 1-20C alkyl, halo, NO2, CN, 1-20C alkoxy, 1-20C alkylamino, OH, 6-20C aryl, 1-20C alkylthio, amino, 6-20C aryloxy, 2-20C heteroaryl, 4-20C heterocycle, 2-20C alkenyl, 2-20C alkynyl and/or 2-20C carbocyclic;R3, R4 = H, 1-20C alkyl, 1-20C alkoxy, 6-20C aryl, 6-20C aryloxy, 2-20C heteroaryl, 4-20C heterocycle, 2-20C alkenyl, 2-20C alkynyl and/or 2-20C carbocyclic;R5, R6 = 1-20C alkyl, halo, NO2, CN, 1-20C alkoxy, 1-20C alkylamino, OH, 6-20C aryl, 1-20C alkylthio, amino, 6-20C aryloxy, 2-20C heteroaryl, 4-20C heterocyclic, 2-20C alkenyl, 2-20C alkynyl and/or 2-20C carbocyclic;k = 0-3;p = 0-4; andm, n = 0-2.Preferred Components: The benzoindole-based dye comprises an N-aryl electron donor and an acidic functional group electron acceptor. The electron donor is a benzo(cd) indole, and the electron acceptor is acid group (-COOH). The highest occupied molecular orbitals are localized near the electron donor and lowest unoccupied molecular orbitals are localized near the electron acceptor. The highest occupied molecular orbitals and the lowest unoccupied molecular orbitals are separated by a bond angle of 25-55 degrees . SPECIFIC COMPOUNDS - 2 Compounds (I) are specifically claimed i.e. 2-cyano-3-(5-(5-(2,6,7,8-tetrahydro-2-(9,9-dimethyl-9H-fluorene-2-yl)-1-phenylbenzo(cd)indole-4-yl)thiophene-2-yl)thiophene-2-yl)acrylic acid of formula (Ia) and 2-cyano-3-(5-(5-(2,6,7,8-tetrahydro-2-(9,9-dimethyl-9H-fluorene-2-yl)-1-phenylbenzo(cd)indole-5-yl)thiophene-2-yl)thiophene-2-yl)acrylic acid.    EXAMPLE - 4-Bromo-2,6,7,8-tetrahydro-1-phenylbenzo(cd)indole (0.6 g), tributyl(5-(thiophene-2-yl)thiophene-2-yl)tin (0.88 g), tetrakis(triphenylphosphine)palladium (0.096 mmol), lithium chloride (0.41 g) and dimethyl formamide (30 ml) were stirred at 100 degrees C for 12 hours. The mixture was further worked up to give 2,6,7,8-tetrahydro-1-phenyl-4-(5-(thiophene-2-yl)thiophene-2-yl)benzo(cd)indole (compound F1). Compound (F1) (0.70 g), 2-iodo-9,9-dimethylfluorene (0.84 g), anhydrous potassium carbonate powder (0.49 g), copper bronze (0.11 g), 18-crown-6 (0.07 g) and 1,2-dichlorobenzene (40 ml) were refluxed for 48 hours. The reaction mixture was worked up to give 2,6,7,8-tetrahydro-2-(9,9-dimethyl-9H-fluorene-2-yl)-1-phenyl-4-(5-(thiophene-2-yl)thiophene-2-yl)benzo(cd)indole (compound F2). Compound F2 (0.47 g) was dissolved in tetrahydrofuran (30 ml) and the mixture was cooled to -78 degrees C under nitrogen atmosphere. n-Butyl lithium (1.25 ml) was added dropwise to the mixture for 10 minutes while the mixture was vigorously stirred. The mixture was stirred at 0 degrees C for 1 hour and maintained at 0 degrees C for another hour. The mixture was cooled to -78 degrees C, and dry dimethylformamide (1 ml) was added to the mixture at once. The temperature of the mixture was raised to room temperature and the mixture was stirred overnight and worked up to give 5-(5-(2,6,7,8-tetrahydro-2-(9,9-dimethyl-9H-fluorene-2-yl)-1-phenylbenzo(cd)indole-4-yl)thiophene-2-yl)thiophene-2-carbaldehyde (compound F3). Compound F3 (0.29 g) and cyanoacetic acid (0.060 g) were dried under vacuum and then acetonitrile (20 ml) and piperidine (0.046 ml) were added to it. The mixture was refluxed for 6 hours and the mixture was cooled down and worked up to give 2-cyano-3-(5-(5-(2,6,7,8-tetrahydro-2-(9,9-dimethyl-9H-fluorene-2-yl)-1-phenylbenzo(cd)indole-4-yl)thiophene-2-yl)thiophene-2-yl)acrylic acid (0.29 g and 91% yield).