New semiconducting copolymers based on benzobisthiazole show excellent environmental stability in high-humidity air, which is an unusual performance for semiconducting polymers, along with OFET mobilities of as high as 0.26 cm(2)/Vs, even with disordered thin-film structures. With these unique features, these new copolymers are fascinating materials with high processability, mobility, and stability as active layers for printable electronics.