In the present invention discloses the production of bisphenol BA-aliphatic amine based hydrophobic polybenzoxazines coated paper developed for proximate pH indicator kit application. The bisphenol BA was prepared using phenol and 4-hydroxybenzaldehyde in the presence of acid catalyst. The different types of benzoxazines were prepared using bisphenol BA (BBA), aliphatic amines (n-butyl amine (ba), n-hexyl amine (ha), 2-ethylhexyl amine (2-eha), dodecyl amine (dda), and octadecylamine (oda)) and paraformaldehyde through Mannich condensation reaction. The structural behaviour of prepared bisphenol BA and corresponding benzoxazines were characterised by FTIR, 'HNMR and MASS spectroscopic techniques. The curing behaviour of benzoxazines was studied by DSC analysis. The ring opening polymerisation of BBA-ba, BBA-ha, BBA-2eha, BBA-ddaand BBA-oda was observed at 234, 236, 236, 240 and 243 °C respectively. The thermal stability of polybenzoxazine was studied thermogravimetric analysis technique. The polybenzoxazines coated cellulose pH indicator paper was prepared and their hydrophobic behaviour was studied by goniometer. The value of water contact angle of poly(BBA-ba), poly(BBA-ha), poly(BBA-2eha), poly(BBA-dda) and poly(BBA-oda) coated paper strip was observed at 122, 124, 125, 130 and 133 ±2° respectively. Further, the polybenzoxazines coated cellulose paper pH indicator kit useful for the determination of high extreme concentration of acid in the range of less than zero (0) pH and high concentration of base in the range between ll pH and l4pH. The polybenzoxazine coated cellulose paper pH indicator kit exhibit orange colour in 0.0 pH, dark orange in -1,0 pH and light red in -1.5 pH and dark red in -1.8 pH. Similarly, the polybenzoxazine coated cellulose paper pH indicator kit exhibit light violet colour in 1 lpH, dark violet in 12 pH and light blue in 13 pH and dark blue in 14 pH. The polybenzoxazine coated cellulose paper pH kit can be used for more than 5 cycles.