S-allyl-b-N-[(2-hydroxyphenyl)methylene]hyrazinecarbodithioate) (1, H 2 L), the Schiff base of dithiocarbazate with unsaturated allyl substitution, can act as a new tridentate SNO ligand H 2 -L and react with cobalt(II) nitrate hexahydrate to form the novel linear trinuclear isovalence Co(II) complex, [Co 3 (H-L) 2 (L) 2 ] 2C 2 H 5 OH (2). The compounds were characterized by elemental analysis, infrared, and ultraviolet spectroscopy. Compound 2 was also characterized by single-crystal X-ray analysis and crystallizes in the orthorhombic space group, Pbcn, with a = 30.643(1) Å , b = 9.118(4) Å , c = 19.017(7) Å , a = b = c = 90°, V = 5312.95 Å 3 , Z = 4, and R 1 = 0.0790, (wR 2 ) = 0.1223. The six-coordinate central Co(II) atom is bonded to two deprotonated metal-containing ligands. The terminal Co(II) atoms are in a square planar SNON four-coordinate environment and connected to the central Co(II) by N-atoms from the ligand backbone. For quantifying the intermolecular interactions in crystal lattice, the new d norm surface and the breakdown of fingerprint plots have been used for visualizing and exploring the compound 2.