Morphological, electrochemical, and photovoltaic stabilities of the poly[benzodithiophene-bis(decyltetradecylthien) naphthothiadiazole] (PBDT-DTNT):phenyl-C61-butyric acid methyl ester (PC71BM) solar cells were promoted by the pre-designed supramolecules on the basis of reduced graphene oxide (rGO) nanosheets. Nanostructures consisted of the pristine rGO, grafted-rGO/PBDT-DTNT, rGO-polythiophene (GPTh) electrospun nanofiber, grafted-rGO/PBDT-DTNT electrospun nanofiber and rGO/PBDT-DTNT samples. The reduction in photovoltaic characteristics during air aging was the steepest for the unmodified PBDT-DTNT:PC71BM solar cells. From rGO based photovoltaics towards the rGO/PBDT-DTNT modified ones possessing the well-patterned PBDT-DTNT nanofibers, the slopes of graphs decreased. The most stabilized devices were fabricated on the basis of PBDT-DTNT:PC71BM:rGO/PBDT-DTNT active layers (power conversion efficiency (PCE) from 6.09% for upon-fabricated to 4.87% for 1 month aged systems) for having the most red-shifted and intensified absorbance, the largest phase separation, the lowest impedance responses and the highest photovoltaic characteristics during 1 month air aging (short circuit current density (J(sc)) of 12.09 mA/cm(2), fill factor (FF) of 63%, open circuit voltage (V-oc) of 0.64 V, hole mobility (mu(h)) of 5.3 x 10(-5) cm(2)/V s, electron mobility (mu e) of 7.9 x 10(-4) cm(2)/V s, charge transfer resistance (R-tr) of 431 Omega cm(2) and PCE of 4.87%). The GPTh/PBDT-DTNT/PC71BM (J(sc) = 10.31 mA/cm(2), FF = 49%, V-oc = 0.55 V, R-tr = 796 Omega cm(2) and PCE = 2.78%) and grafted-rGO/PBDTDTNT/PBDT-DTNT (J(sc) = 10.98 mA/cm(2), FF = 56%, V-oc = 0.60 V, R-tr = 539 Omega cm(2) and PCE = 3.69%) electrospun nanofibers also imparted the stabilization of devices within 1 month.