Polymer dye

A method for producing a polymer dye having a repeating unit represented by the formula (I):

• wherein each of R1, R2, and R3, which may be identical or different, is a monocyclic carbocyclic group which may have a substituent, a condensed polycyclic carbocyclic group which may have a substituent, a monocyclic heterocyclic group which may have a substituent, or a condensed polycyclic heterocyclic group which may have a substituent, wherein R1 is a divalent group, and R2 and R3 are monovalent groups;
• D is an organic dye group;
• and n is an integer of from 0 to 10,
• wherein the polymer dye has a number-average molecular weight of from 500 to 500,000,
• the method comprises:
• reacting an amino compound represented by the formula (II):
• and a dihalogeno-compound represented by the formula (III):
• X-D-X (III),
• wherein X is a halogen atom,
• in the presence of a catalyst containing a palladium compound and a phosphine compound, and a base.