In this work, the successful manufacturing of 3D-printed, photoactive reactor parts could be demonstrated by using a TiO2-polypropylene composite filament produced from TiO2 powder and PP granulate for the photocatalytic reduction of nitrobenzene and the photocatalyzed synthesis of quinaldine. Different photocatalytically active reactor inserts were manufactured and characterized with respect to their hydrodynamic and reactive properties. In addition to this, the suitability of a solid acid as alternative to a homogeneous acid catalyst was evaluated. The immobilized solid acid was successfully applied in the photocatalytic synthesis of quinaldine. The results give evidence that the immobilization of the solid acid not only influences the activity but also the selectivity of the reaction. The presented results clearly show that 3D-printed reactor parts containing (photo)chemically active components can be manufactured. While issues like the stability of the support material have to be addressed in the future, the advantages associated with manufacturing chemically active components with additive manufacturing technologies were demonstrated. Beside the advantages of immobilizing (photo)catalysts, such as avoiding a down-stream separation, reactor designs can be modified and characterized quickly to achieve an optimal reaction performance. The applied rapid prototyping possibilities will accelerate development cycles. Furthermore, the use of several components made from different chemically active components allows for tailoring (photo)chemical reactors, eventually allowing the development of multi-functional reactors for cascade reactions with high performance and selectivities.