Nowadays, the idea that molecules can be used as basis in an electronic device arouses scientific community around the World. The information storage capacity from technological demand a growing exponentially and depend on the development of Nanoscience. The aim is the storage of data quicker and the miniaturization of the devices and because of this, one of the most promising strategies is based on the concept of bistability between two electronic states of a molecule passing from an initial state (OFF) to a finale state (ON) under the influence of an external stimulus.

In this thesis, on one hand, we synthetized successfully new anionic spin crossover materials with 1,2,4- triazole derivatives as coordinated ligand being used in multifunctional materials, obtaining trimers with spin transition above room temperature and in addition, with a record TTIESST in this kind of compounds. Moreover, with a cation exchange, we carried out to tune new compounds modifying theirs magnetic properties.

On the other hand, we have studied several composites since a conductor polymer and spin transition compounds, specifically trimers and polymers with 1,2,4- triazole derivative ligands, with the purpose of modify the electrical and thermoelectric properties and create a synergy between the magnetic, electrical and thermoelectric behavior.