The prospect of de-oiled seed cakes of African star apple (ASA) and Silk cotton (SCS) as a source of bio-oil was investigated using slow pyrolysis. The study was carried out at a temperatures range of 300-450 degrees C with a heating rate of 10 degrees C min(-1) for 60 min residence period in a nitrogen atmosphere. The optimum bio-oil yields for SCS (33.1%) and for ASA (48.3%) were achieved at 400 degrees C. The Bio-char yield decreases from 300 degrees C to 450 degrees C (38%-28%) for ASA seedcake which could be due to greater primary decomposition of the biomass samples. A similar trend also observed for SCS with a lowest bio-char yield of 32% at 450 degrees C. The GC-MS analysis showed that ASA bio-oil has an acids (25.15%), phenolics (18.35%), and hydrocarbons (18.58%) as the major compounds. N-containg compounds (38.17%), carboxylic acid (23.79%), and phenolic (16.57%) were the dominant compounds in SCS bio-oil. The FT-IR absorption peak showed at 1660 cm(-1)(C = N stretching) with higher intensity for SCS bio-oil. At optimum temperature 400 degrees C, 72% of ASA feedstock was converted into bio-oil and gaseous products (conversion), while 68% conversion was obtained from SCS at optimum temperature 400 degrees C. (C) 2019 Elsevier Ltd. All rights reserved.