Vol. 15 | No. 2 |1573-1587| April - June | 2022 ISSN: 0974-1496 | e-ISSN: 0976-0083 | CODEN: RJCABP http://www.rasayanjournal.com http://www.rasayanjournal.co.in Rasayan J. Chem., 15(2), 1573-1587(2022) http://doi.org/10.31788/RJC.2022.1526443 This work is licensed under a CC BY 4.0 license. A REVIEW ON BIOLOGICAL ACTIVITIES: 1,3,4- THIADIAZOLE AND ITS DERIVATIVES Kantabathina Hemanth 1 , Kaviarasan Lakshmanan 2 , Kalirajan Rajagopal 1 , Piyongsola 3 and Gowramma Byran 1,  1 Department of Pharmaceutical Chemistry, JSS College of Pharmacy, JSS Academy of Higher Education & Research Ooty, Niligiris, TamilNadu 643001 2 Department of Pharmaceutical Chemistry, College of Pharmacy, JSS Academy of Technical Education, Noida 3 Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research Ooty, Niligiris, TamilNadu 643001  Corresponding Author: Gowrammab@rediffmail.com ABSTRACT Thiadiazole is a heterocyclic molecule made up of one sulphur atom, two nitrogen atoms, and two double-bonded 5- membered ring systems. Heterocyclic compounds having biological activity serve a significant role in medicinal chemistry. More than one or two heteroatoms are also included in the five-membered ring, including thiadiazole, oxazole, thiazole, azole, pyrrole, triazine, and others. Thiadiazole has been shown to have anticancer, anti- inflammatory, anti-diabetic, antimicrobial, antifungal, antibacterial, antiviral, anti-tuberculosis, anticonvulsant, antidepressant, antileishmanial, and other biological effects. Keywords:Thiadiazole, heterocyclic, 1,3,4-thiadiazole, biological activity, anti-inflammatory. RASĀYAN J. Chem., Vol. 15, No.2, 2022 INTRODUCTION Heterocyclic compounds are essential in medicinal chemistry because they have wide biological action. Furan, thiophene, and pyrrole are five-membered heterocyclic compounds, each with a heteroatom. In five-membered ring structures, one or more heteroatoms are present, such as thiadiazole, oxadiazole, azole, thiazole, pyrrole, and triazine, among others. As a result, heterocyclic chemistry continues to demonstrate synthetic organic chemists' knowledge and enormous scientific curiosity. The thiadiazole is a 5-membered heterocyclic molecule with one S atom, two N atoms, and two double bonds that have been claimed to have a wide range of biological activities. Thiadiazole has the chemical formula C2H3N2S with an unsaturated ring structure. Thiadiazoles have four isomeric forms: 1,3,4- thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, and 1,2,3-thiadiazole 1,2 . S N N S N N N S N S N N 1,2,3-thiadiazole 1,2,5-thiadiazole 1,2,4-thiadiazole 1,3,4-thiadiazole 1 2 3 4 Amongst which 1,3,4- thiadiazole to be considered as one of the most significant and well-known heterocyclic nuclei, as it is reported with various pharmacological performance such as anticancer, anticonvulsant, analgesic, anti-inflammatory, anti-tubercular, anti-leishmanial, antimicrobial, anti- hepatitis-B, antioxidant, diuretic, antihypertensive, central nervous system (CNS) depressant, anti- diabetic, antiepileptic actions, and molluscicidal.