Spinel-NiMn2O4 (NMO) nanofibers of high aspect ratio, high surface area (50 m(2) g(-1)) and homogeneous pore size distribution are fabricated by electrospinning process and characterized by XRD, FTIR, XPS, BET, FESEM, TEM techniques. Further, multifunctional properties (energy storage properties, magnetic and electrical properties) of NMO nanofibers are also examined. High specific capacitance (C-s) of 410 (+/- 5) F g(-1) at 1 Ag-1, good rate capability and high cycling stability (up to 5000 cycles) are demonstrated by NMO nanofibers. Furthermore, NMO-based solid-state symmetric supercapacitor (SSSC) shows a high C-s of 170 (+/- 5) F g(-1) at 0.5 Ag-1 in potential range of 0.0V-2.0V and exhibits excellent energy density of similar to 95 Wh kg(-1) and power density of 1030 W Kg(-1). The above storage properties i.e. high energy density and output voltage of 2.0 V are further supplemented by lighting up a red colored LED (1.8V @ current 20 mA) at least for 5 min. The ionic diffusion coefficient of NMO based electrode is found to be similar to 4.84 x 10(-11) cm(2) s(-1). Magnetic and dielectric properties of NMO nanofibers are also examined and results are discussed. (C) 2017 Elsevier B.V. All rights reserved.