A new Co(II)-hexaborate containing [Co{B 6 O 7 (OH) 6 } 2 ] 2-building blocks decorated with 1-cyanopiperazinium organic cation; (C 5 H 11 N 3 )[Co{B 6 O 7 (OH) 6 } 2 ]Á 4H 2 O (1-CPCoB6) was synthesized from aqueous solution and the crystals were grown by the slow evaporation technique and characterized by means X-ray diffraction, IR UV-Vis and fluorescence spectroscopy measurements, elemental analysis and TDA-TG thermal analysis. The powder and single crystal XRD analysis revealed that the isolated pure crystals belong to the triclinic system. The structure exhibits interesting porous 3D-hydrogen-bonded network built by [Co{B 6 O 7 (OH) 6 } 2 ] 2-monomers. The cyanopiperazinium dications are filled in the free void channels of the inorganic framework and interact by means extensive hydrogen bonds. This hydrated mixed hexaborate thermally decomposed in multiple steps involving dehydration and release of organic cation leading to a novel unknown phase which undergoes crystallization. Moreover, the fluorescent and antimicrobial properties of 1-CPCoB6 have also been carried out, showing a red photoluminescence and a promising enhancement of biological activity of reported material in comparison with its parent reactants.Electronic supplementary material The online version of this article (