Triazine is the chemical species of six-membered heterocyclic ring compound with three nitrogens replacing carbon-hydrogen units in the benzene ring structure. The names of the three isomers indicate which of the carbon-hydrogen units on the benzene ring position of the molecule have been replaced by nitrogens, called 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine respectively. Symmetrical 1, 3, 5-triazine is the common.  Triazines are prepared from cyanic acid amide by trimerization (1, 3, 5-triazine). Pyridine is the aromatic nitrogen heterocyclic compound having only one nitrogen, and diazines are with 2 nitrogen atoms, triazine having three nitrogen and tetrazines are with 4 nitrogen atoms on the benzene ring system. Triazines are weak base. Triazines have much weaker resonance energy than benzene, so nucleophilic substitution is preferred than electrophilic substitution. Heterocyclic bearing a symmetrical s-triazines or 1, 3, 5-triazines moieties, represent an interesting class of compounds possessing a wide spectrum of biological activities such as anti-cancer, antiviral, fungicidal, insecticidal, bactericidal, herbicidal and antimicrobial, antimalarial agents. They also find applications as dyes, lubricants and analytical reagents.   Key words: Triazine, Nucleophilic substitution, Cyanuric chloride, 1, 3, 5-triazine, s- Triazine