**1. Introduction**

Heterocycles are cyclic compounds containing atoms other than carbons and hydrogens and may be synthesized or occur naturally in plants, animals and human beings. In particular, nitrogen-containing heterocycles are considered very important building blocks in the chemical and pharmaceutical industries (among others) since they can be used as catalysts, protecting groups, chiral auxiliaries and chemical intermediates.

Azoles are 5-membered nitrogen-containing aromatic heterocycles, to which thiazoles and pyrazoles belong. Pyrazoles contain two nitrogens in a 1,2 linkage while thiazoles contain nitrogen and sulfur in a 1,3 linkage. Pyrazoles and thiazoles are useful pharmacophores with a potential for various therapeutic applications.

This chapter will focus on the following as it relates to pyrazoles and thiazoles reported during 2015–2022: (i) strategies and perspectives on the synthesis of 1,5-disubstituted pyrazoles and 2,4,5-trisubstituted thiazoles derivatives and (ii) their therapeutic and biological evaluations.
