Two‐Photon 3D Printing in Metal–Organic Framework Single Crystals

Abstract Two‐photon polymerization (TPP) is a micro/nano‐fabrication technology for additive manufacturing, enabling 3D printing of polymeric materials using ultrafast laser pulses. In this work, two‐photon polymerization is realized inside a metal–organic framework (MOF) crystal. Intricate structures are built in the porous crystal to create a microstructure‐in‐crystal hybrid. Furthermore, the MOF can be removed by acid treatment to release the printed structure. The two‐photon polymerization inside the crystal has the potential for MOF sensing device fabrication and data storage applications. In the future development, printing different materials in the same MOF crystal for creating functional 3D devices is hoped.