A new soluble and thermally stable nonlinear optical (NLO) polyimide was synthesized by adding both tricyanopyrroline (TCP)- and tricyanofuran (TCF)-based NLO chromophores into the polymer backbone. The NLO polyimide (PI-II) bearing two different chromophores with different sizes has a glass transition temperature of $146^{circ}C$ and exhibits good film forming properties. The electro-optic coefficient of the film was 84 pm/V at $1.3{mu}m$ under a poling field of 80V/${mu}m$, even though PI-II has an unusually high chromophore density of approximately 20 wt% of TCP chromophores and 23 wt% of TCF chromophores. Even with a overall chromophore loading of 43 wt%, no severe aggregation effect was observed for the sample that exhibited a relatively high EO coefficient.