In this work we demonstrate a large electric field-induced bipolar strain similar to 0.40% in Li, Ta and Sb modified BNTKNN ((1x) Bi0.5Na0.5TiO3xK0.47Na0.47Li0.06 Nb0.74Sb0.06Ta0.2O3) system. The morphotropic phase boundary (MPB) of the system between rhombohedral and tetragonal phases lies in the range 0.02x0.06, beyond which all compositions (up to x<0.15) were found to be tetragonal. A clear trade-off between the large strain values and achievable d33, kp for a particular composition was noted. It is shown that while for x=0.03, d33 169pC/N, kp 49% and strain similar to 0.13% were obtained, for x=0.08 with 0.40% strain, d33 and kp values decreased drastically.