In conclusion, this study reports a new green and low-cost synthetic procedure that has been developed to join GO nanosheets to produce folded 3D crosslinked GO networks by coordination chemistry to form irregular micrometer length tubes. Crosslinking of GO is much more effective using Zn2+ and Sr2+ at room temperature (24°C) than with Ca2+, which requires the temperature to be raised to 34°C to achieve the same crosslinking density. The synthesis of the new calcium alginate composites reported in this study thus show an example of the potential use of these GO networks to reinforce other materials showing a very significant increase in the storage modulus and a more homogeneous structure. Of note, is that this synthetic process is in keeping with the principles of green chemistry and in good agreement with the sustainable non-hazardous synthetic routes with no demands on thermal or sonic energy consumption. These 3D networks of GO coordinated with divalent cations (Ca, Zn, Sr or others) will enable broadening of the field towards the synthesis of new continuous carbon materials and reinforced composites such as alginates with unique electric, thermal, oxidative, and chemical properties with very promising applications in fields of electronics, optics, energy, environmental science and biotechnology in the near future.