INTRODUCTION Schiff base ligands and their metal complexes exhibit numerous biocidal activities 1-2 , such as antitumour 3 , antibiotic 4 and antiviral 5 . Schiff bases have attracted the interest of many chemists due to their ability to coordinate with various metal ions and also their reactions with microbial DNA and inhibiting tumor growth 6 , which have been reported by several workers in the past. Such ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org Est. 1984 An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2013, Vol. 29, No. (2): Pg. 655-659 Spectral and Antimicrobial Screening of Cu(II), Ni(II) and Co(II) Coordination Compounds with Nitrogen Oxygen and Sulphur Containing Tridentate Schiff Base B. K. RAI*, SANJAY KUMAR 1 , RAHUL ANAND 2 and ASHOK PANDEY 3 Department of Chemistry, L. N. T. College, B. R. A. Bihar University, Muzaffarpur, India. 1 Department of Chemistry, Jagdam College, Chapra, India. 2 University Department of Chemistry, J. P. University, Chapra, India. 3 Department of Chemistry, M. H. Degree College, Tarwara, Siwan, India. *Corresponding author E-mail : binodkr_rai@yahoo.co.in (Received: March 28, 2013; Accepted: May 03, 2013) ABSTRACT A series of coordination compounds have been prepared with tridentate Schiff base ligands, 2 ethyl-[(hydroxy propyl)]- 3, 1 (4H) quinazoline- 4-semicarbazone [EHPQS) and 2-ethyl-[(hydroxy propyl)]- 3, 1 (4H) quinazoline- 4-thiosemicarbozone [EHPQT]. The obtained complexes were characterized by molar mass, elemental analysis, infrared spectra, electronic spectra, magnetic susceptibility molar conductance analysis and spectral studies show that the Schiff base EHPQS/ EHPQT behaves as tridentate chelating agent and coordinated to metal ions via, azomethine nitrogen alcoholic oxygen atom and with either carbonyl or thione sulphur atom of ligand. The electronic spectra and molar susceptibility of the complexes show a distorted octahedral geometry for Cu(II) complexes where as octahedral geometry for Co(II) and NI(II) metal ions. The Schiff base ligand and their metal complexes have been tested for antimicrobial activities against Gram positive bacteria; Staphylococci aureus and Gram negative bacteria Escherichia coli. Key words : EHPQS/EHPQT/Schiff bases/ Co(II), Ni(II) and Cu(II)/ Antimicrobial studies. ligands have unusual configuration, structural liability and are sensitive to molecular environment. As a continuation of our interest in the field of the chemistry of, the present communication deals with the synthesis, spectral and antimicrobial studies of Co(II), Ni(II) and Cu(II) complexes with Schiff bases derived from condensation of 2-ethyl –[3-(hydroxy propyl)]-3,1(4H) quinazoline -4 one with semcarbazide/thiosemicarbazide hydrochloride.