novel spinel hollow nanofibers were synthesized by a convenient single-nozzle electrospinning technique. based on the composition and morphology results by x-ray diffraction (xrd), scanning electron microscopy (sem) and transmission electron microscopy (tem), a 'gas-push' model was proposed to elucidate the formation mechanism of hollow nanofibers during calcination. photoluminescence (pl) properties of calcined znal2o4: xcr(3+) and mgal2o4: xcr(3+) nanofibers were investigated systematically. under an excitation of 400 nm or 530-550 nm ((4)a(2g)-> t-4(1g) or (4)a(2g ->)(4)t(2g) transitions of cr3+ ions), an emission band at 675-725 nm including a sharp emission line (r-line) at similar to 687 nm with several vibrational sidebands was obtained. compared with the spectroscopic properties of znal2o4: xcr(3+) nanofibers, the emission band was broadened and the decay lifetime was shortened for mgal2o4: xcr(3+) nanofibers. by calculation of crystal field strength, the value of d-q/b is estimated to be 3.25 and 2.72 for znal2o4: xcr(3+) and mgal2o4: xcr(3+) nanofibers, respectively. the difference of crystal field strength gives a good explanation of the spectroscopic and decay evolution between znal2o4: xcr(3+) and mgal2o4: xcr(3+) nanofibers.