In the present work, an attempt has been made to develop a chalcone based benzoxazine (1,3-bis(3,4-dihydro-3-phenyl-2H-benzo[1,3]oxazin-6-yl)prop-2-en-1-one) using 1,3-bis(4-hydroxyphenyl)prop-2-en-1-one, aniline and formaldehyde at appropriate conditions. The molecular structure of the developed benzoxazine was confirmed by FT-IR and NMR analysis. The thermal properties were studied with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). From the data resulted, it was observed that the curing temperature of chalcone based benzoxazine appears at 205 °C. Similarly, the maximum degradation temperature was obtained at 474 °C with a char yield of 43% and the glass transition temperature was noticed at 234 °C. The blending of Chal-Bz with conventional bismaleimides such as 4, 4′-diaminodiphenylsulfone based bismaleimide (BMI-M) and 4, 4′-diaminodiphenylmethane based bismaleimide (BMI-S) results in the improved thermal stability to an appreciable extent. Further, the effect of incorporation of bio based benzoxazines synthesized from cardanol-aniline (CrAb) and eugenol-aniline (EuAb) to the Chal-Bz thermal behavior was also studied. In addition, the effect of catalysts (4-hydroxy phenylmaleimide HPM, 4-Amino Phenol AP, 4-hydroxy acetophenone HAP) on thermal curing properties of benzoxazines was also studied to bring down the polymerization temperature by creating supplementary potential sites for polymerization. From that catalytic study, it was found that the incorporation of 10 wt% of HAP reduces the value of Tp (158 °C) more efficiently than that of other catalysts. Data resulted from different studies, it can be suggested that the polymer blends of chalcone based benzoxazine and conventional bismaleimide can be used in the form of encapsulants, sealants, adhesives, and matrices in the fields of microelectronics and automobile industries for enhanced performance.