Three different compounds have been synthesized by keeping X as variable: X=O/S/NH for Compound- A/Compound-B/Compound-C respectively. Electronegati vity of oxygen for urea X:O=3.5 and of sulfur for thiourea X:S=2.4 and of nitrogen+hydrogen for guani dine X:NH=3.1+2.2=5.3. So the X=NH shows the maximum electronegativity with combined effect of e lectronegativity of nitrogen and hydrogen, whereas X=O has two lone pairs and X=S has also two pair of electrons, but in case of NH moiety the electronegativity of nitrogen and hydrogen exceeds the electronegativity of oxygen and sulfur: NH (5.3 ) > O (3.5) > S (2.4). The spectral data for the absorp tion for the three compounds was compared with gall ic acid for the plot was calculated by the equation: y =0.022x-0.1458 (R2=0.982) and found that the antioxidant property of the compounds have the ment ioned profle: Compound-C>Compound- B>Compound-A. Compound-C is guanidine moiety having X=NH so according to the highest electronegativity profile this is more potent than other two when compared with the total reducing cap acity property. (Compound-A: 272.8μg, Compound-B:317μ g, C ompound-C:384.9μ g) It was expressed as GAE means that reducing power of 10mg of each compound is equivalent to reducing power of μ g of gallic aci d or expressed as μgGAE/mg of compound.