We present here the synthesis, characterization, and flash photolysis study of [(F8TPP)Fe-II(CO)(THF)] (1) {F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2-)}. Complex 1 crystallizes from THF/heptane solvent system as a tris-THF solvate, [(F8TPP)Fe-II(CO)(THF)](.)3THF (1(.)3THF), with ferrous ion in the porphyrin plane (C61H52F8FeN4O5; a = 11.7908(2) Angstrom, b = 20,4453(2) Angstrom, c = 39.9423(3), alpha = 90degrees, beta = 90degrees, gamma = 90degrees; orthorhombic, P2(1)2(1)2(1), Z = 8; Fe-N-4(av) = 2.00 Angstrom; N-Fe-N (all) = 90.0degrees). This complex (as 1(.)THF) has also been characterized by H-1 NMR {six-coordinate, low-spin heme; CD3CN, RT, delta 8.82 (s, pyrrole-H, 8H), 7.89 (s, para-phenyl-H, 8H), 7.46 (s, meta-phenyl-H, 4H), 3.58 (s, THF, 8H), 1.73 (s, THF, 8H) l, 2 H NMR (pyrrole-deuterated analogue) [(F8TPP-d(8))Fell (CO)(THF)] (THF)] {THF, RT, delta 8.78 ppm (s, pyrrole-D)}, C-13 NMR (on (CO)-C-13-enriched adduct) {THF-d(8), RT, delta 206.5 ppm; CD2Cl2, RT, delta 206.1 ppm}, UV-vis {THF, RT, lambda(max), 411 (Soret), 525 nm}, and IR 293 K, solution, nu(CO) 1979 cm(-1) (THF), 1976 cm(-1) (acetone), 1982 cm(-1) (CH3CN)} spectroscopies. In order to more fully understand the intricacies of solvent-ligand binding (as compared to CO rebinding to the photolyzed heme), we have also synthesized the bis-THF adduct [(F8TPP)Fe-II(THF)(2)]. Complex 2 also crystallizes from THF/heptane solvent system as a bis-THF solvate, [(F8TPP)Fe-II(THF)21-2THF (2-2THF), with ferrous iron in the porphyrin plane (C60H52F8FeN4O4; a = 21.3216(3) Angstrom, b = 12.1191(2) Angstrom, c = 21.0125(2) Angstrom, alpha = 900, beta = 105.3658(5)degrees, gamma = 90degrees; monoclinic, C2/c, Z = 4; Fe-N-4(av) = 2.07 Angstrom; N-Fe-N (all) = 90.0degrees). Further characterization of 2 includes UV-vis {THF, lambda(max), 421 (Soret), 542 nm} and H-1 NMR {six-coordinate, high spin heme; THF-d(8), RT, delta 56.7 (s, pyrrole-H, 8H), 8.38 (s, para-phenyl-H, 8H), 7.15 (s, meta-phenyl-H, 4H)} spectroscopies. Flash photolysis studies employing 1 were able to resolve the CO rebinding kinetics in both THF and cyclohexane solvents. In CO saturated THF {[CO] similar to 5 mM} and at [1] congruent to 5 muM, the conversion of [(F8TPP)Fe-II (THF)(2)] (produced after photolytic displacement of CO) to [(F8TPP)Fe-II(CO)(THF)] was monoexponential, with k(obs) = 1.6 (+/-0.2) x 10(4) s(-1). Reduction in [CO] by vigorous Ar purging gave k(obs) congruent to 10(3) s(-1) in cyclohexane. The study presented in this report lays the foundation for applying fast-time scale studies based on CO flash photolysis to the more complicated heterobimetallic heme/Cu systems.