The fabrication and testing of metal-insulator-metal (MIM) diodes on a flexible substrate for microwave and mm-wave applications are presented. The diodes utilized octadecyltrichlorosilane (OTS), which self assembles to form a thin, pin holes free insulator. Preliminary electrical analysis shows that the diodes have a typical zero bias resistance of approximately 80 kΩ, zero-bias curvature coefficient (γ_ZB) of approximately 5.5 V−1, and voltage responsivity of 3.1 kV/W at a frequency of 1 GHz, and are produced with over 90% device yield. The fabrication process is simple and cost effective, environmentally friendly, and demonstrates the possibility of roll-to-roll volume manufacturing of MIM diodes.