Graphdiyne (GD), a novel carbon allotrope with a 2D structure comprising benzene rings and carbon-carbon triple bonds, is successfully integrated with ZnO nanoparticles by a wet chemistry method. An ultraviolet photodetector based on these graphdiyne: ZnO nanocomposites exhibits significantly enhanced performance in comparison with a conventional ZnO device. GD may have diverse applications in future optoelectronics.