Three new poly(4,4-dialkylcyclopentadithiophene (PDOCPT) derivatives, poly(4,4-dialkylcyclopentadithiophene-co-pyridine) (PDOCPTPy), poly(4,4-dialkylcyclopentadithiophene-co-phenanthroline) (PDOCPTPh), and poly(cyclopenta[2,1-b:3,4-b']dithiophen-4-one) (P