A series of fluorinated methanes complexed with linear molecules (H₃CF–OCS, H₂CF₂–OCS, HCF₃–OCS, and HCF₃–CO₂) have been studied by ab initio (Gaussian 03W) and semi-empirical (ORIENT) calculations, and Fourier-transform microwave (FTMW) spectroscopy.  Experimental measurement of rotational spectra for several isotopically substituted species of each complex has enabled a structure determination for each dimer, while Stark effect measurements have provided dipole moment components; evidence of large amplitude motions were observed in the spectra of HCF₃–CO₂ and H₃CF–OCS.  All experimental structures have an approximate antiparallel alignment of the monomers, with one hydrogen atom on the fluorinated methane subunit involved in a C–H…O interaction with the oxygen atom of OCS or CO₂.  Theoretical and experimental results will be presented, and structural trends in the series of complexes as a function of the degree of fluorination on the alkyl halide subunit will be discussed.