Highlights: 3D printable functional inks incorporated with graphene and carbon nanotube nanoparticles were well-formulated by manipulating their rheological performance The frame with ultralight structure (0.076 g cm−3) and high-efficiency electromagnetic interference shielding (61.4 dB) was assembled 3D-printed c-SE module was in situ integrated onto the electronics, affording multiple functions of electromagnetic compatibility and thermal dissipation. Electromagnetic interference shielding (EMI SE) modules are the core component of modern electronics. However, the traditional metal-based SE modules always take up indispensable three-dimensional space inside electronics, posing a major obstacle to the integration of electronics. The innovation of integrating 3D-printed conformal shielding (c-SE) modules with packaging materials onto core electronics offers infinite possibilities to satisfy ideal SE function without occupying additional space. Herein, the 3D printable carbon-based inks with various proportions of graphene and carbon nanotube nanoparticles are well-formulated by manipulating their rheological peculiarity. Accordingly, the free-constructed architectures with arbitrarily-customized structure and multifunctionality are created via 3D printing. In particular, the SE performance of 3D-printed frame is up to 61.4 dB, simultaneously accompanied with an ultralight architecture of 0.076 g cm−3 and a superhigh specific shielding of 802.4 dB cm3 g−1. Moreover, as a proof-of-concept, the 3D-printed c-SE module is in situ integrated into core electronics, successfully replacing the traditional metal-based module to afford multiple functions for electromagnetic compatibility and thermal dissipation. Thus, this scientific innovation completely makes up the blank for assembling carbon-based c-SE modules and sheds a brilliant light on developing the next generation of high-performance shielding materials with arbitrarily-customized structure for integrated electronics. [ABSTRACT FROM AUTHOR]