ESR measurements of [CLPOT-(4-X-TEMPO)] inclusion compounds (CLPOT = 2,4,6-tris(4-chlorophenoxy)-1,3,5-triazine, and 4-X-TEMPO = 4-substituted-2,2,6,6-tetramethyl-1-piperidinyloxyl radical) with 1D organic-radical molecular chains constructed in organic 1D nanochannels used as templates were conducted in the range of temperatures from 4.2 to 300 K. The peak-to-peak line width (ΔBpp) of all isotropic ESR spectra of the [CLPOT-(4-X-TEMPO)] was much narrower in the whole temperature range than the estimation based on the Van Vleck’s formula for the second moment of the rigid lattice model. In addition, the line profiles of all ESR spectra of the [CLPOT-(4-X-TEMPO)] became Lorentzian in the whole temperature range, compared with our previous results using tris(o-phenylenedioxy)cyclotriphosphazene (TPP) as templates in which the ESR profiles were temperature-dependent. These results indicate that the narrower ESR line width of the [CLPOT-(4-X-TEMPO)] may be caused not by motional narrowing but by 3D exchange interaction even at room temperature although the magnitude was less than 1 K.

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