The synthesis, characterization, thermal decomposition and antimicrobial studies of the perchlorate, nitrate, thiocyanate, chloride and bromide complexes of iron(III) with 2,3-(diimino-4'-antipyrinyl) butane (BDAP) have been done. The characterization of the complexes were done by elemental analysis, molar conductance in non-aqueous solvents, IR and UV-Vis spectra and magnetic moment studies. The phenomenological, kinetic and mechanistic aspects of the complexes have been done by TG and DTG techniques. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation were computed. The molar conductance and the infrared spectral studies reveal that one of the perchlorate ions is coordinated bidentately, two of the nitrate ions, thiocyanate ions, chloride ions and bromide ions are coordinated in a monodentate fashion. The UV-Vis spectral and magnetic moment data suggests a high spin octahedral geometry around the iron(III) ion in all the complexes. The mechanism for the thermal decomposition is random nucleation with one nucleus on each particle representing ‘Mampel Model’ for all the complexes except chloride complexes which has the mechanism phase boundary reaction representing spherical symmetry. Antimicrobial analyses of the ligand and the complexes reveal significantly higher activity for the metal complexes than the ligand against microorganisms. The structure activity relationship analysis of the complexes shows that, thiocyanate complexes have highest activity against bacteria and fungus.