The charge mobility in a new hole transporting polymer, poly(2,6-bis(thiophene-2-yl)-3,5-dipentadecyldithieno3,2-b;2′,3′-dthiophene) (PBTDTT-15), and its blend with (6,6)-phenyl-C70-butyric acid methyl ester (PC70BM) in a weight ratio of 1:3 at ambient atmosphere condition was investigated using time-of-flight (TOF) photoconductivity and photoinduced charge extraction by linearly increasing voltage (PhotoCELIV) techniques. The bulk heterojunction based photovoltaic (PV) blend (PBTDTT-15:PC70BM (1:3)) exhibited a promising power conversion efficiency (PCE) of 3.23% under air mass 1.5 global (AM 1.5G) illumination of 100mW/cm2. The charge mobility and recombination properties of the best performing cells were investigated. The hole mobility in the pure PBTDTT-15 was in the range of 4 × 10−4 cm2/(V s), which was reduced almost 5 times in the PBTDTT-15:PC70BM (1:3) blend. The PhotoCELIV transient observed for the photovoltaic (PV) blend was dominated by electrons, with the charge mobility of the order of 10−3 cm2/(V s), and a weak shoulder at a long time scale due to holes. The effective bimolecular recombination coefficient (β) obtained for the PV blend deviated significantly from the Langevin recombination coefficient (βL) indicating a phase-separated morphology. The obtained results indicate that the PBTDTT-15:PC70BM blend can be potential for organic solar cell applications.