The novel copper(II) coordination compound derived from 4-formyl-3-hydroxy-2- naphtoic acid thiosemicarbazone ligand (H3L) has been synthesized using the procedure published earlier [1] and characterized by single-crystal X-ray crystallography and EPR method. The crystal has a molecular structure which essentially results from the packing of neutral molecules [Cu(H2L)NO3(dmf)] (1). The thiosemicarbazone ligand acts as monodeprotonated tridentate ligand being coordinated to copper atom through its phenolic oxygen (Cu-O 1.906(3) Å), azomethine atom (Cu-N 1.941(3) Å) and sulphur atom in its thione form (Cu-S 2.249(3) Å). The copper(II) ion is pentacoordinate. The coordination number of copper is completed by the NO3 - group and dimethylformamide molecule. The carboxylic group remains undeprotonated and forms with the phenolic oxygen atom an intramolecular hydrogen bond.figureFig.1. The molecular structure (a) and EPR spectrum (b) of the complex 1 The polycrystalline sample of the compound 1 was investigated by EPR method at 298 K. The EPR parameters (gII = 2.211; g┴ = 2.049; g0 * = 2.103) suggest a square pyramid structure, which is in accordance with the data of X-ray analysis.