The one-pot synthesis of g-C3N4-MU isotype heterojunction has been produced by the thermal polycondensation method by mixing different ratios of precursors between melamine and urea. The isotype heterojunction g-C3N4-MU samples were characterized by X-ray diffraction spectroscopy, scanning electron microscope and energy-dispersive X-ray-spectroscopy, UV-Visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The band-gap energy of these photocatalysts reveals that they can work well under visible light. The photocatalytic performance of the samples was investigated over the photodegradation of reactive orange-16 (RO-16) dye and tetracycline hydrochloride (TC-HCl) under visible light irradiation. The isotype heterojunction of g-C3N4-M6U10 showed the highest degradation of 95 and 85.6% for RO-16 and TC-HCl, respectively under irradiation time of 100 and 120 min. The major reactive species was identified as O-center dot(2)-. Moreover, the reusability of the photocatalyst was investigated up to 3 cycles with good efficiency. The present synthesized isotype heterojunction g-C3N4-MU could be applied as a facile pathway for synthesis and as an effective pathway to resolve various environmental problems. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.