A 3d-4f heterobimetallic material with mixed anions, Ho2Cu(TeO3)(2)(SO4)(2), has been prepared under hydrothermal conditions. Ho2Cu(TeO3)(2)(SO4)(2) exhibits both thermochromism and the Alexandrite effect. Variable temperature single crystal X-ray diffraction and UV-vis-NIR spectroscopy reveal that changes in the Cu-II coordination geometry result in negative thermal expansion of axial Cu-O bonds that plays a role in the thermochromic transition of Ho2Cu(TeO3)(2)(SO4)(2). Magnetic studies reveal an effective magnetic moment of 14.97 mu B. which has a good agreement with the calculated value of 15.09 mu B.