Organic colorant corresponding to the following structure: eD - pi-conjugated chromophore - L - A in which - eD represents an electron donor segment, said electron donor segment (eD) being an amino group of (Z 1)(Z 2)N- type, with Z 1 and Z 2, identical or different, representing an alkyl group optionally substituted or an aryl group optionally substituted, a substituted alkyl or aryl group being an alkyl or aryl group substituted by a group or several groups, identical or different, chosen from a halogen; an amine; a diamine; a carboxyl; a carboxylate; an aldehyde; an ester; an ether; a hydroxyl; a halogen; an aryl optionally substituted; an alkyl optionally substituted; an amide; a sulphonyl; a sulphoxide; a sulphonic acid; a sulphonate; an acyl; a vinyl; a hydroxyl; an epoxy; a phosphonate; an isocyanate; a thiol; a glycidoxy; an acryloxy; a thiophene; a furan; a selenophene and salts thereof, - L represents a covalent bond or a spacer segment, said spacer L being an alkenylene or alkynylene chain optionally substituted or an arylene chain optionally substituted, a substituted alkenylene, alkynylene or arylene chain being an alkenylene, alkynylene or arylene chain having one substitution or several substitutions, identical or different, this or these substitutions corresponding to halogen atoms or to aliphatic groups optionally comprising at least one heteroatom, - A represents an electron attractor segment able to form a covalent bond with a semi-conductor, said electron acceptor segment being a carboxylic acid group, a cyanoacrylic acid group, a phosphonic group, a dithiocarboic group or a group corresponding to any of the following formula: wherein the pi-conjugated chromophore comprises at least two aromatic rings, at least one of which is a thiophene type ring, and wherein said chromophore has at least one unit chosen from: in which - the radicals R 47 to R 64, identical or different, represent a hydrogen, an alkyl group optionally substituted or an aryl group optionally substituted, - X 8 is chosen from S, Se and O, and - X 6 and X 7 are such that one of the two represents S and the other is either Se, or O. - eD represents an electron donor segment, said electron donor segment (eD) being an amino group of (Z 1)(Z 2)N- type, with Z 1 and Z 2, identical or different, representing an alkyl group optionally substituted or an aryl group optionally substituted, a substituted alkyl or aryl group being an alkyl or aryl group substituted by a group or several groups, identical or different, chosen from a halogen; an amine; a diamine; a carboxyl; a carboxylate; an aldehyde; an ester; an ether; a hydroxyl; a halogen; an aryl optionally substituted; an alkyl optionally substituted; an amide; a sulphonyl; a sulphoxide; a sulphonic acid; a sulphonate; an acyl; a vinyl; a hydroxyl; an epoxy; a phosphonate; an isocyanate; a thiol; a glycidoxy; an acryloxy; a thiophene; a furan; a selenophene and salts thereof, - L represents a covalent bond or a spacer segment, said spacer L being an alkenylene or alkynylene chain optionally substituted or an arylene chain optionally substituted, a substituted alkenylene, alkynylene or arylene chain being an alkenylene, alkynylene or arylene chain having one substitution or several substitutions, identical or different, this or these substitutions corresponding to halogen atoms or to aliphatic groups optionally comprising at least one heteroatom, - A represents an electron attractor segment able to form a covalent bond with a semi-conductor, said electron acceptor segment being a carboxylic acid group, a cyanoacrylic acid group, a phosphonic group, a dithiocarboic group or a group corresponding to any of the following formula: wherein the pi-conjugated chromophore comprises at least two aromatic rings, at least one of which is a thiophene type ring, and wherein said chromophore has at least one unit chosen from: in which - the radicals R 47 to R 64, identical or different, represent a hydrogen, an alkyl group optionally substituted or an aryl group optionally substituted, - X 8 is chosen from S, Se and O, and - X 6 and X 7 are such that one of the two represents S and the other is either Se, or O. - the radicals R 47 to R 64, identical or different, represent a hydrogen, an alkyl group optionally substituted or an aryl group optionally substituted, - X 8 is chosen from S, Se and O, and - X 6 and X 7 are such that one of the two represents S and the other is either Se, or O.