In summary, we have demonstrated a facile approach based on complex-forming and viscoelasticity-enhancing bPEs to transform liquid-like bioinks into gels that enable extrusionbased 3D bioprinting at a physiological temperature (37 °C). Swift self-assembly of oppositely charged bPEs was harnessed to lend initial structural robustness to photocurable precursor solutions, improve their extrudability and post-printing recovery, and support inter-layer adhesion in the printed structures. This, to the best of our knowledge, is the first demonstration of harnessing electrostatic self-assembly of block polyelectrolytes to create a scaffolding for cellcontaining bioinks. Depending on the chemical composition, bPEs were able to either enhance the shear and tensile strengths of the crosslinked hydrogels by forming interpenetrating networks or serve as sacrificial micellar additives, which were quickly removed by diffusion post-printing. Further improvements in the already satisfactory cytocompatibility of the PEC hydrogels are envisioned by varying the lengths of the neutral and the charged blocks and the nature of the charged moieties as well as incorporation of enzyme-or photocleavable sites along the PEO backbone. Additional physico-mechanical features provided by the PEC network, such as tunable shear moduli and salt responsiveness, enabled the flexible platform to meet the increasing demands on advanced materials for biomedical applications and tissue engineering. Our pioneering approach based on electrostatic self-assembly of bPEs thus represents a competitive alternative to state-of-the-art approaches of temperature-induced pre-gelation, mitigating their drawbacks and offering new perspectives for future bioink design. Since any aqueous biopolymer solution -especially those which are currently not extrudable due to their liquid-like propertiescan be supplemented with bPEs, the strategy demonstrated here excels by its unique versatility and feasibility.