Spin crossover (SCO) systems are functional molecular materials possessing labile electronic configurations switchable between the high- (HS) and low-spin (LS) states in response to external stimuli (temperature, pressure, light, sorption, phase transition). In the HS and LS states SCO materials reveal differences in magnetism, optical and dielectric properties, colour and structure. SCO materials are one of the most important examples of bistable molecular materials with potential applications as sensors, electronic memories and in opto-electronics. A rational control of the SCO-properties is required, in particular at nano-metric scale, if they have to be successfully integrated into functional devices. The present research proposal has two research lines. The first one includes: 1a) Development of nano-structured cooperative spin crossover metallorganic frameworks (SCO-MOFs) following the ‘bottom-up’ synthetic approach; 1b) Nanoscale patterning of SCO-MOFs; 1c) Detection of magnetic, optical and dielectric bistability in SCO-MOFs at nanometric scale in external electric field. The second line will be guided towards: 2a) Development and investigation of new charged and neutral SCO systems with liquid crystalline properties (SCO-LSs) with strong intermolecular hydrogen bonding; 2b) Study of SCO properties of SCO-LCs under external electric field.