Directed assembly of nanoparticles is a promising alternative for original nanoparticle organizations. New kinds of optical properties are expected when semi-conductive or metallic nanoparticles are concerned. Using liquid crystal matrices oriented by their interfaces, it is possible to induce anisotropic nanoparticle organizations. We can then investigate the influence of these matrices on the optical properties of the nanoparticles. I will show how to create hierarchical arrays of oriented topological defects in thin smectic films that act as efficient traps for a specific localization and orientation of nanoparticles [1]. I will show how specific nanoparticle assemblies can be obtained, depending on the nanoparticle size and shape. Fluorescent nanorods trapped in smectic dislocations become strictly oriented along a single direction, providing, a fine control of the polarization of the emmitted single photons [2]. Similarly the orientation of gold nanorods leads to the control of their luminescence as well as of their plasmon resonance by light polarization. I will show that, when the nanoparticle concentration is increased, single chains are formed, and can lead to a strong anisotropic electromagnetic coupling between the particles [3]. We are not only capable of linearly confining the particles, but also of varying the inter-particle interactions and thus modifing their optical properties which are sensitive to the inter-particle distance [4]. [1] D. Coursault, Soft Matter 12 (2016) 629. [2] L. Pelliser et al, Adv. Funct. Mat. 25 (2015) 1719. [3] D. Coursault et al., Adv. Mat. 24 (2012) 1461. [4] D. Coursault et al., ACSNano 9 (2015) 11678.