Benefiting from their structural flexibility and solution processability, organic-inorganic metal halide hybrids with efficient white-light emission present a great promise for solid-state lighting and display applications. However, most of these reported high-performance single-component white-light materials contain lead. Herein, we report a "green" organic zinc halide, [(N-AEPz)ZnCl4]Cl (1; N-AEPz = N-aminoethylpiperazine), exhibiting prominent bluish-white-light emission with a photoluminescence quantum efficiency as high as 11.52%. Such a value is among the highest in the reported metal halide white-light emitters. Mechanism studies disclose that the broad-band emission is ascribed to the synergistic work of organic salts and inorganic clusters. This work would incent research on single-component white-light materials for next-generation display and lighting technologies.