Synthesis of functional materials via biocatalytic methods using enzymes is of great interest due to its advantages which include environmental compatibility, economical synthesis and ease of processability. Research in the area of flame-retardant (FR) materials is of growing interest due to their numerous applications in clothing, construction, aviation and telecommunications. Halogen based flame retardant polymers, until recently were a cost effective solution to FR materials but are now banned due to the release of toxic gases. Thus, there exists the need to develop environmentally-safe and economical sound processable polymers with efficient flame retardant properties. We have recently shown that biocatalytically synthesized siloxane based copolyesters, copolyamides and copolyimides have great potential as FR materials.1-3 In this paper, we present the synthesis, characterization, thermal and flame retardant properties of this novel class of organo-siloxane copolymers. We also discuss the effect of cross-linking and additives on these polymers in thermal decomposition and flame retardant properties.