TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises reacting butane-2,3-dione with an aryl aldehyde of formula (Ar1CHO) and arylamine of formula (Ar2NH2) in acidic conditions and isolation of substituted 1,4-dihydro-pyrrolo(3,2-b)pyrrole compounds of formula (II) (representative of (I)).Ar1, Ar2 = aryl or heteroaryl (both optionally substituted).Preferred Process: The process is carried: in the presence of acetic acid, preferably glacial acetic acid, and Bronsted acid as catalyst, and above 50 degrees C, preferably around 100 degrees C; and in the presence of acid with negative base-10 logarithm of the acid dissociation constant of less than 2 that is aryl sulfonic acid preferably p-toluenesulfonic acid or benzenesulfonic acid as catalyst. (II) is precipitated from cooled reaction mixture. Preferred Components: (I) is of formula (Ia), (Ib) or substituted 2,5-diphenyl-1,4-dihydro-pyrrolo(3,2-b)pyrrole compounds of formula (Ic).Ar1-Ar4 = aryl or heteroaryl (both optionally substituted). Preferred Definitions:    R3 = H; and    R1, R2 = derivatives of benzene, optionally substituted in ortho, meta or para position with NO2, CN, OCH3, SO2CH3, SO3H, halo, CHO, COOH, CONH2 or SF5.    SPECIFIC COMPOUNDS - 39 Compounds (I) are specifically claimed e.g. 2,5-diphenyl-1,4-bis(4-methylphenyl)-1,4-dihydropyrrolo(3,2-b)pyrrole of formula (IIa), 1,2,4,5-tetra(4-methylphenyl)-1,4-dihydropyrrolo(3,2-b)pyrrole, 2,5-di(naphthalen-1-yl)-1,4-bis(4-methylphenyl)-1,4-dihydropyrrolo (3,2-b)pyrrole, 2,5-di(anthracen-9-yl)-1,4-bis(4-octylphenyl)-1,4-dihydropyrrolo(3,2-b)pyrrole and 2,5-bis(4-cyanophenyl)-1,4-bis(4-methylphenyl)-1,4-dihydropyrrolo(3,2-b)pyrrole.    EXAMPLE - 5 ml Glacial acetic acid, 1 mmol butane-2,3-dione, 2 mmol p-tolylamine, 2 mmol benzaldehyde and 0.2 mmol p-toluenesulfonic acid were added to flask. The resulting mixture was stirred at 100 degrees C for 3 hours. Then reaction mixture was cooled. Resulting precipitate was filtered, washed with cold glacial acetic acid, recrystallized followed by drying to give 2,5-diphenyl-1,4-bis(4-methylphenyl)-1,4-dihydropyrrolo(3,2-b)pyrrole.