In this work, we report the enhanced photocatalytic behaviour of copper tin hydroxide (CuSn(OH)₆)-based catalyst materials for the degradation of methylene blue dye prepared by a simple co-precipitation technique. The X-ray diffraction study showed that the as-synthesized sample belongs to tetragonal phase copper tin hydroxide, whereas the existence of CuO–SnO₂ composite nature was confirmed for the 600 °C-calcined sample. The signatures of Sn–O and Cu–O vibrations were confirmed from the peaks observed in 600 °C-calcined sample at 682, 618 and 538 cm⁻¹. The formation of interconnected small cubical nanoparticles was seen from the morphological studies. The selected area electron diffraction pattern of as-prepared sample showed mostly dots, which indicated the polycrystalline nature of the sample, whereas, the crystal lattices corresponding to SnO₂ and CuO composite were noticed for 600 °C-annealed sample. The absorption edge shift-induced variation in optical energy band gap (from 3.31 to 2.51 eV) values of as-prepared and annealed samples were noticed. The blue and green emission bands observed in the photoluminescence spectra may be due to the defect levels and oxygen vacancies in the samples. The as-synthesized CuSn(OH)₆ sample has shown a highest photocatalytic degradation efficiency of 86% towards the MB dye degradation under visible light illumination.