A main goal of nowadays spin crossover (SCO) research is the development of materials suitable for technological applications. Multifunctional materials, combining the SCO effect with an additional property (e.g. luminescence, NLO, etc.) would notably broaden the scope of applicability. Currently, we focus on the development of spin-switchable metal organic frameworks with extended pore-size that could act as multifunctional materials by the mere incorporation of a functional guest. Starting from Hofmann-type networks - {Fe[Mᴵᴵ(CN)₄]∞} (M=Ni, Pd, Pt) layers stacked by symmetrical bifunctional N-ligands - an extension of the [Mᴵᴵ(CN)₄]²⁻ fragment was performed, by addition of an acetylene unit to the CN fragment (resulting in C≡C-C≡N fragment). This led to second generation Hofmann-type networks with hysteretic SCO behavior beyond room-temperature and extended pore size.