A new method to aid large-area solution processing of organic small molecule semiconductors is reported. A thermally degradable poly(propylene carbonate) (PC) binder is added to a solution of soluble precursor to a tetrabenzoporphyrin to increase its viscosity, allowing for the use of large-area methods such as inkjet printing, slot coating, or blade coating. This method is used to make bulk heterojunction solar cells with a p-i-n type structure.