ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY http://dx.doi.org/10.14233/ajchem.2014.16992 INTRODUCTION Nowadays, the increasing microbial resistance to anti- biotics led the scientist to search for new compounds with potential effects against pathogenic bacteria. The most specta- cular advances in medicinal chemistry have been made when heterocyclic compounds played an important role in regulating biological activities. Many Schiff bases are known to be medi- cinally important and are used to design medicinal compounds. Nitro and halo derivatives of Schiff bases are reported to have antitumor and antimicrobial activities 1 . Antifungal and anti- microbial activities of various Schiff bases have also been reported 2 . Fungi toxicity of some Schiff bases has investigated by Sahu et al 3 . Similarly high antimicrobial activities of some Schiff bases were reported by Gawad et al 4 . Many Schiff bases are known to be medicinally important and are used to design medicinal compounds 5 . Cinnmaldehyde is a well-established natural antimicrobial compound. Several studies 6 showed that the presence of a lone pair of electrons in a sp 2 hybridized orbital of nitrogen atom of the azomethine group is of considerable chemical and biological importance. Literature Synthesis, Characterization and Antimicrobial Potential of Novel Conjugated Schiff Bases AMEER FAWAD ZAHOOR 1 , MUHAMMAD YOUSAF 1,* , ASIM MANSHA 1 , SHAZIA NAHEED 1 , MATLOOB AHMAD 1 , ANBREEN ANJUM 2 , KIRAN AFTAB 1 , ABDUL GHAFFAR 2 , SAJJAD AHMAD 3 and ALI IRFAN 1 1 Department of Chemistry, Government College University, Faisalabad, Pakistan 2 Department of Applied Chemistry and Biochemistry, Government College University, Faisalabad, Pakistan 3 University of Engineering and Technology Lahore, Faisalabad Campus, Faisalabad, Pakistan *Corresponding author: E-mail: dryousafsmor@gmail.com Received: 7 January 2014; Accepted: 24 March 2014; Published online: 1 September 2014; AJC-15874 Anthracenylamine and naphthylamine were reacted with 1, 3-cyclohexadienone and 1, 4-benzoquinone in order to prepare four (1, 2, 3 & 4) conjugated Schiff bases for the evaluation of their antibacterial as well as antifungal activities. The results of their activities were compared with standard drugs against three strains of bacteria as well as three strains of fungi and they showed that the Schiff base 4 (C34H22N2O) exhibited good inhibition zones against all the strains of bacteria (10.74 ± 0.65, 10 ± 0.675, 10.65 ± 0.75 mm) as well as fungi (9.15 ± 0.815, 10.25 ± 0.55, 10.5 ± 0.575 mm) as compared to others (1, 2 & 3). The Schiff base 3 (C26H24N4) showed better potential for S. aureus (10 ± 0.856 mm) strain of bacteria and A. alternate (10.5 ± 2.150 mm) strain of fungi. Its activity against other two strains of bacteria and fungi was also better than other two Schiff bases (1 & 2). The Schiff base 2 (C26H22N2) exhibited reasonable activity against B. subtilus (10 ± 0.715 mm) and A. alternate (8.55 ± 0.015 mm). The compound (1) showed least antibacterial (4.5 ± 0.815, 5 ± 0.716, 4.75 ± 0.950 mm) as well as antifungal (4 ± 0.575, 4.15 ± 0.570, 6.5 ± 1.725 mm) activity. From the results it is concluded that delocalization of π electrons has the positive influence on the antimicrobial potential of the titled Schiff bases. Thus these Schiff bases may serve as a basis for the chemical modifications directed towards the development of a new class of antibacterial agents. Keywords: Conjugated Schiff base, Bacterial strains, Fungal strains, Activity. Asian Journal of Chemistry; Vol. 26, No. 18 (2014), 6159-6162 also justifies that Schiff bases are important class of compounds in medicinal field. They show biological applications including antibacterial, antifungal and antitumor activities 7,8 . Latter it was found that antimicrobial agents reduce or completely block the growth and multiplication of bacteria and are helpful in the treatment of various infectious diseases like meningitis, malaria, tuberculosis, pneumonia, AIDS, etc. Schiff bases derived from aromatic amines and aromatic alde- hydes have a wide variety of applications in many fields, for example, biological, inorganic and analytical chemistry 9 . Increase in the mortality rate associated with infectious diseases is directly related to bacteria that exhibit multiple resistance to antibiotics. The lack of effective treatments is the main cause of this problem. The development of new antibacterial agents with novel and more efficient mechanisms of action is defini- tely an urgent medical need. Keeping in mind the medicinal potential of Schiff bases, also assuming the bactericidal effects of anthracene and naphthalene, the novel conjugated Schiff bases were prepared by reacting 1,3-cyclohex-adione and 1,4- benzoquinone with anthracenyl amine and naphthylamine for evaluating their antimicrobial potential.