Lanthanide metal-organic frameworks (Ln-MOFs) represent a promising class of multicolor luminescence nanomaterials with broad application prospects. However, the fabrication of high-quality, tunable multicolor Ln-MOFs for optical applications remains highly challenging due to the lack of suitable processing methods. In this work, an integrated device was introduced that used dielectric barrier discharge (DBD) liquid plasma for synthesis, which was coupled with in situ spectral monitoring, enabling the fabrication of multicolor heterojunction Ln-MOFs. This approach facilitates precise multicolor control from red, orange-red, yellow, and pale-green to green by adjusting the Tb