The complex bis(perchlorate) tetrakis(pyrazole) copper(II) has been prepared and characterized by single crystal X-ray analysis, FT-IR, UV-VIS spectroscopy and thermal methods. [Cu(ClO4)(2)(pyzl)(4)] crystallizes in the monoclinic system, space group C2/c, with a = 14.5186(11), b = 9.9513(7), c = 15.8564(11) angstrom, beta = 115.5290(10)degrees V = 2067.2(3)angstrom(3) and z = 4. The molecular and crystal structure are stabilized by inter and intramolecular hydrogen bonds. The complex formation kinetics was studied at 310 nm. The activation parameters of the complex formation kinetics were determined as, Delta H-#: 200 kJ/mol, Delta S-#: 268 J/K. mol. The FT-IR spectra has been measured and assigned in the range of 4000-400 cm(-1). The Cl-O and N-H stretching vibrations confirms the presence of intramolecular hydrogen bonds. The magnetic moment of the complex was found to be 1.73 BM. The fluorescence quenching of pyrazole by Copper(II) was also studied in methanol.