The morphology, chemical composition, microstructure and electrical properties of BC3 thin films subjected to melting by a nanosecond laser pulse were investigated. The original films were formed by pulsed laser co-deposition of B and C on a sapphire substrate at 150 and 350 °C. Morphological changes in the films depended on their initial structure. However, the structure “frozen” after irradiation in both films was attributed to the B-saturated graphite-like phase, the local composition of which varied due to the formation of inclusions of amorphous boron carbide. Before and after irradiation, the films showed a weakly decreasing dependence of the sheet resistance with increasing temperature from 4.2 to 330 K. After pulsed laser irradiation, the sheet resistance of the films decreased by ~ 2.6 times.