The combined temperature and excitation wavelength effects on the photophysical (fluorescence quantum yields and lifetimes) and photochemical behavior of the rotamer mixture of trans-1,2-di(2-naphthyl)ethene(trans-2,2'-DNE) has been investigated in nonpolar solvent. By using a refined procedure of the principal component analysis (PCA), applied to the fluorescence spectra of the rotamer mixture, the spectral properties and the relative abundances of the three distinct rotamers at room temperature were derived. Furthermore, the rate constants of their radiative and reactive processes were obtained, so suggesting a complete picture of all of the deactivation pathways of the lowest excited singlet state of the trans-2,2'-DNE rotamers.