Ferromagnetic resonance (FMR) of a room temperature organic based mixed valent Vanadium Hexacyanochromate magnet K$_{1.54}$V$^{II}_{0.77}$V$^{III}_{0.08}$[Cr$^{III}$(CN)$_{6}$](SO$_{4})_{0.16}$3.1H$_{2}$O.*

Recently, organic materials both magnetic and non-magnetic have been receiving significant attention for their potential applicability in spintronics devices such as spin-valves, memory devices, spin-transistors etc. Here we report magnetic and X-band FMR studies of an organic based mixed valent Vanadium Hexacyanochromate magnet K$_{1.54}$V$^{II}_{0.77}$V$^{III}_{0.08}$[Cr$^{III}$(CN)$_{6}$](SO$_{4})_{0.16}$3.1H$_{2}$O with an ordering temperature well above room temperature ($>$340K). Temperature dependencies of FMR parameters including intensity, linewidth, resonance field will be discussed in terms of the coexistence of long-range magnetic ordering and spin-glass-like behavior in this material. [1] {\O}yvind Hatlevik et. al. Adv. Mater. \textbf{11}, 914 (1999).