The growth of one-dimensional (1D) fluorinated copper-phthalocyanine (CuPcF(16)) on gold (Au) nanoparticles (NPs) is studied by electron tomography. The shape of the 1D structure and its geometrical relationship with the associated Au NP are determined by a three-dimensional reconstruction analysis combined with high-resolution electron microscopy. The CuPcF(16) molecules nucleate at the <110> edge of the Au nanoparticle and grow parallel to a {111} facet of the particle along a direction close to <121>. This implies that the maximum diameter of the 1D structure is limited by the width of the <110> edge of the Au particle.