Variations in the predictable level of heavy metals ions have an uncompromising influence on living being and their surroundings. Real sample analysis was used to identify the heavy metal ions by using colorimetric and fluorescence techniques. The interaction of metal ions with the receptor has produced observable signals as measured by its photophysical changes. Nitrogen-containing heterocyclic compounds are the greatest weapons for identifying heavy metal ions, owing to their diverse reactivity, readily available substrate, and exquisite photophysical property. The main goal of this mini-review is to examine the current advancements in the structural analysis of nitrogen-containing heterocyclic compound-based fluorescence and colorimetric sensors. The interaction between receptor and metal by electron transfer mechanism and its wide applications have been developed and used for the sensing of heavy metal ions in the past ten years by various research groups about selectivity, sensitivity, reversibility, pH effect, stoichiometric ratio, binding constant, LOD values, and real-time applications.