In recent years, highly conductive, three-dimensional (3D) printable electrodes have received tremendous attention in various research fields. Printable electrodes must display the following characteristics: (i) high conductivity, (ii) cost-effectiveness, (iii) durability under extreme environmental conditions (heat and moisture), and (iv) processability on low-cost plastic substrates (indispensably, polyethylene terephthalate (PET) substrate). I will introduce a variety of chemical technologies for resolving the aforementioned issues for the realization of 3D-printed electronics. A stretchable conductor is one of critical prerequisites for achieving various form of stretchable electronics. It is demonstrated that an addition of non-ionic surfactant in 3D-printable Ag flake-based composite pastes, allows for a critical reduction in resistance variation under an external strain. In addition, we formulate the composite pastes employing electrostatically assembled-hybrid carbons and polystyrene-polyisoprene-polystyrene tri-block copolymer elastomer for the fabrication of multi-stack printed piezoresistive pressure sensor arrays. Also, in a viewpoint of enabling energy unit-embedded circuitries, we have designed functional composite materials for printing directly in-plane energy storage units. Prerequisites in materials will be discussed for achieving high-performance multi-stack printed micro-supercapacitors.