This research work consists of the synthesis of Schiff bases and sulphonamides derivatives of nicotinic and isonicotinic acid hydrazide by adopting different synthetic chemical transformations and tested of their antioxidant and bioactivities. All compounds were entirely characterized by a variety of spectroscopic techniques like EI-MS and 1H-NMR. Four chapters have been included in this critique based on the broad literature and it is regarding the three series of the synthetic compounds. Everyone has its own references, compounds tables, figures, schemes and numbering. Chapter-1 It is consisting of broad literature review related to the common introduction of Schiff bases and nicotinic acid and its reaction, various synthetic protocols and biological background. It has been also studied the several biological activities which are done on compounds. This chapter describes the synthesis of Schiff bases of nicotinic acid hydrazides 131-163 and studies of their antioxidant, antileishmanial, urease, α-glucosidase, anti glycations, α-chymotrypsin, acetylcholinetorase, butyrylcholinesterase, tyrosinase, xanthine oxidase, anticancer and antimicrobial activities. Chapter-2 Describes the synthesis of Schiff base derivatives of isonicotinic acid hydrazides 40-69 and studies of their antioxidant, antileishmanial, antiglycation, urease, α-glucosidase, α-chymotrypsin, tyrosinase, xanthine oxidase, anticancer and antimicrobial activities. Chapter-3 Describes the syntheses of sulfonamide derivatives of nicotinic and isonicotinic acid hydrazides 77-99 and their urease inhibitory activity, antioxidant, antiglycation, immunomodulatory and antimicrobial activities. In chapter-4, we describe bioassay protocol used for the all compounds.