Narrow band gap conjugated polymers employing cross-conjugated donors useful in electronic devices

A method of synthesizing a narrow band gap conjugated polymer, comprising steps of:

• copolymerizing at least one first monomer or oligomer having the formula:
• wherein G is a leaving group suitable for a cross-coupling polymerization reaction,
• FG is selected from the group consisting of substituted C1-C36 hydrocarbyl, unsubstituted C6-C20 aryl, substituted C6-C20 aryl, unsubstituted C3-C20 heteroaryl, substituted C3-C20 heteroaryl, unsubstituted C0-C36 hydrocarbylene C6-C20 aryl-C0-C36 hydrocarbyl, substituted C0-C36 hydrocarbylene, C6-C20 aryl, C0-C36 hydrocarbyl, F, Cl, Br, I, CN, —R2, SR2—OH, —OR2, —COOH, —COOR2, —NH2, —NHR2, or NR2R3, where R2 and R3 are independently selected from a C1-C24 hydrocarbyl group;
• m is an integer of at least 1;
• Y is selected from the group consisting of S, BR3, PR3, Se, Te, NH, or Si, wherein R3 is a C1-C24 hydrocarbyl group;
• and
• FG′ is selected from the group consisting of unsubstituted C6-C20 aryl, substituted C6-C20 aryl, unsubstituted C3-C20 heteroaryl and substituted C3-C20 heteroaryl;
• a second monomer selected from the group consisting of monomers that provide the following structural units in the copolymer:
• and
• optionally a third monomer comprising double or triple bonds separated by a single bond;
• thereby forming a reaction mixture;
• adding a catalyst to the reaction mixture;
• heating the reaction mixture and catalyst;
• cooling, purifying, washing, and drying the reaction mixture to form the narrow band gap conjugated polymer having a band gap of 0.1 to 1.2 eV.