<p>Thermal degradation of lignocellulosic biomass waste, under oxygen-deprived conditions, produce biochar which is a carbon-rich solid product suitable for several applications. Its quantity and quality depend on several parameters; a few important ones are the type of biomass, reaction temperature, and time. In this study, effects of temperature and reaction time on pyrolysis of <i>Erythrina indica</i> (EI) biomass were examined in a tubular reactor at temperatures of 400–700&#xa0;°C and reaction times of 60–120&#xa0;min. The resulting pyrolytic products, especially biochar, underwent a comprehensive characterization employing advanced analytical techniques. The results revealed a clear dependence of product yield and quality on pyrolysis temperature and reaction duration. The surface morphology of fibrous lignocellulosic biomass transformed from compact to a porous biochar structure during pyrolysis. The experimental BET analysis showed that maximum surface area (250.76&#xa0;m²/g) biochar obtained at 500&#xa0;°C for 60&#xa0;min, while XRD indicated partial graphitization at higher pyrolysis temperatures. The bio-oil exhibited acidic characteristics (pH = 3.2–4.4) and a maximum HHV is obtained at 500&#xa0;°C for 90&#xa0;min. The regression model was used to explore the combined effects of process variables, and pyrolysis conditions corresponding to maximum response within the experimental domain were identified. These were 506&#xa0;°C and 60&#xa0;min. producing 48.35 wt% yield biochar with 55.64 wt% of fixed carbon, 151.62&#xa0;m²/g of surface area, pH of 9.35, H/C of 0.050, and O/C of 0.377.</p> Graphical abstract <p></p>