<div>Synthesis of crystalline materials is crucial in the field of</div><div>coordination chemistry. In the present work, the reaction</div><div>between the copper and benzene-1,3,5-tricarboxylic acid</div><div>(BTC) ligand is controlled by adjusting the pH of the</div><div>reaction mixture to synthesize two crystalline structures:</div><div>metal-organic framework HKUST-1 and one-dimensional</div><div>coordination polymer Cu(BTC).3H₂O. Single crystals of both</div><div>structures are studied by multi-laser Raman spectroscopy.</div><div>It is found that both crystals exhibit photoluminescence.</div><div>Also, the transformation of HKUST-1 into Cu(BTC).3H₂O is</div><div>demonstrated. This work provides impetus for researchers</div><div>to synthesize large metal-organic crystals.</div>