TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): The substituent-eliminable diketopyrrolopyrrole derivative (I) is obtained by eliminating a solvent-soluble carboxyl group-containing substituent of formula (a) from the substituent-eliminable diketopyrrolopyrrole derivative (I) by applying external stimuli. SPECIFIC COMPOUNDS - 17 Substituent-eliminable diketopyrrolopyrrole derivatives are disclosed e.g. (4-(4-(4-(((tert-butoxy)carbonyl)oxy)phenyl)-2,5-dimethyl-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)phenyl)tert-butyl carbonate of formula (Ia), (4-(4-(4-(((tert-butoxy)carbonyl)oxy)phenyl)-2,5-diethyl-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)phenyl)tert-butyl carbonate, (4-(4-(4-(((tert-butoxy)carbonyl)oxy)phenyl)-2,5-bis(2-ethylhexyl)-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)phenyl)tert-butyl carbonate, (4-(5-(4-(5-(4-(((tert-butoxy)carbonyl)oxy)phenyl)thiophen-2-yl)-2,5-dimethyl-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)thiophen-2-yl)phenyl)tert-butyl carbonate and (4-(5-(4-(5-(4-(((tert-butoxy)carbonyl)oxy)phenyl)thiophen-2-yl)-2,5-bis(2-ethylhexyl)-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)thiophen-2-yl)phenyl)tert-butyl carbonate.    EXAMPLE - 300 mg 3,6-Bis(5-bromothiophen-2-yl)-2,5-bis(2-ethylhexyl)-1H,2H,4H,5H-pyrrolo(3,4-c)pyrrole-1,4-dione, 214 mg 4-(t-butyloxycarbonyl)-oxy-phenylboronic acid, 24 mg tetra(tri-tert-butylphosphine)palladium(O), 388 mg tripotassium phosphate, 10 ml tetrahydrofuran and 2 ml water were added to a flask, and refluxed for 5 hours in argon atmosphere. The resultant mixture was cooled to room temperature, and 100 ml methanol was added to the flask. The precipitate was separated by filtration, purified by a silica gel column chromatography using dichloromethane as solvent, and 170 mg (4-(5-(4-(5-(4-(((tert-butoxy)carbonyl)oxy)phenyl)thiophen-2-yl)-2,5-bis(2-ethylhexyl)-3,6-dioxo-2H,3H,5H,6H-pyrrolo(3,4-c)pyrrol-1-yl)thiophen-2-yl)phenyl)tert-butyl carbonate was obtained as dark blue powder with yield of 42.3%.