To provide a polymer excellent enough in photoelectric 5 conversion efficiency and in light resistance to be suitable for solar cells, also to provide a solar cell using the polymer, and further to provide an electronic product comprising the cell. Embodiments of the present disclosure provide a polymer comprising a repeating unit of the following formula (M1). In the formula, R1 is a substituent group selected from the group 15 consisting of alkyl groups, and alkoxy groups; each R2 is independently a substituent group selected from the group consisting of hydrogen, halogen, alkyl groups, alkoxy groups, and aryl groups; and each X is independently an atom selected from the group consisting of O, S and Se. The embodiments 20 also provide a solar cell having an active layer containing the above polymer and further an electronic product comprising that cell.