Nano plated and high-purity boron carbide (B4C) powder was synthesized via a novel method, based on a solid-state reaction of poly (vinyl alcohol) PVA and boric acid at (200–250) °C in air. The cross-linking between PVA and boric acid was proven by FTIR analysis. The obtained product, a new-type of poly vinyl borate (PVBO), was consecutively pyrolyzed at (700–800) °C for 120min in air (S1); or was ground and heat treated at 250°C for 120min, followed by pyrolysis at (700–800) °C for 120min in air (S2). Both pyrolyzed specimens (S1& S2) were then heat treated at (1375–1475) °C in an Ar flow for (180-120) min, respectively. XRD analysis shows that high purity B4C was obtained from S2 which was pyrolyzed at 750°C and heat treated at 1475°C. Compared to previous methods (commercial or sol-gel etc.), this approach is cost-effective, highly promising, and established a new reaction route in the field of polymer- derived ceramic (PDC).