The preparation and properties of polymers are related to the conditions of synthesis and processing. The structural properties can easily be customized by strictly controlling such conditions. On the other hand, slight variation in some conditions may cause drastic variations in the characteristics of structure, and consequently properties. These conditions are the precursor concentrations, catalyst, time and temperature of curing. Herein we report facile and convenient syntheses of polymers with/without using surfactants and with/without using base or acid as a catalyst at low temperature. Polymers derived from 3-Aminophenol and formaldehyde, furfural alcohol was also used for the syntheses of polymers. These polymers were characterized by different techniques like SEM, EDX, XPS, TGA, FTIR, and Raman spectroscopy. These polymer spheres were converted into carbon spheres which show promising properties for supercapacitors. Later on these nano materials were used for the electrochemical detection of nitrite via cyclic voltammetry and Amperometry with the help of surface modified and carbon paste electrodes. These electrodes are highly selective and sensitive for estimation of nitrite. In addition to electrochemical, fluorogenic sensing of nitrite was also done which was also highly sensitive and selective towards nitrite.