AbstractHerein, the design and synthesis of a couple of CPPs based on thienoacene units (named as IEP‐14 and IEP‐15, stand for IMDEA Energy Polymer numbers 14 and 15) are described, which show high BET surface areas, good photo(thermal) stabilities, and appropriate electronic alignment with TiO₂ to prepare hybrids (named as IEP‐x@T‐10, X = 14 and 15, being 10 wt% of polymer loading). It is shown that the simultaneous UV–vis irradiation of both materials leads to better H₂ production (ca. 925 and 827 µmol g⁻¹ h⁻¹ by IEP‐15@T‐10 and IEP‐14@T‐10, 12 and 11‐fold higher production than bare TiO₂) than the solely irradiation at visible of the CPPs (ca. 124 and 90 µmol g⁻¹ h⁻¹ by IEP‐15@T‐10 and IEP‐14@T‐10 when TiO₂ is photocatalytically inactive). The reason is attributed to the charge‐transfer mechanisms that occur between the counterparts of the hybrid material: in the first case it consists in a Z‐scheme charge transfer mechanism, while in the second one is a sensitization charge transfer mechanism. Both mechanisms are elucidated by advanced techniques. Furthermore, in a gas phase CO₂ photoreduction test, IEP‐15@T‐10 shows sixfold higher CH₄ evolution than TiO₂, which result in a selectivity shift from CO to CH₄ (i.e., >26% greater selectivity than bare TiO₂)_.