Abstract: Structural, optical, dielectric and thermal properties of pure and L-alanine (LA) doped bis-thiourea cadmium acetate (BTCA) crystals have been studied in present investigation. Pure and L-alanine (LA) doped bis-thiourea cadmium acetate (BTCA) crystals have been grown by slow evaporation technique. The crystal system of pure and doped BTCA crystal has been determined by single crystal XRD technique. The shifts in the vibrational frequencies of functional groups of doped BTCA crystal have been identified by FT-IR spectral analysis. The improved optical transparency and large transmission range of doped BTCA crystal has been assessed under UV-visible study. The enhanced optical band gap of LA doped BTCA is found to be 4.83 eV. The thermal stability of doped BTCA crystal was determined by means of thermogravimetric & differential thermal analysis.