Additive manufacturing techniques that use light, such as stereolithography and digital light processing, have transformed the fabrication of complex three-dimensional (3D) structures, enabling advances in biomedical devices, soft robotics, and advanced sensing technologies. Despite this progress, current approaches remain limited by slow printing speeds, restricted material choices, limited resolution, and reliance on complex post-processing, which hinder scalability and practical deployment. This Faculty Early Career Development Program (CAREER) award supports research that seeks to overcome these barriers by developing a new light-based manufacturing approach that directly prints multi-material, multi-scale electronic and photonic structures in a single step. By advancing fundamental understanding of how light interacts with materials to form functional conductors at micro- and sub-micron scales, the award aims to accelerate innovation while reducing material waste, chemical processing, and manufacturing complexity. This research addresses national needs in sustainable and resilient advanced manufacturing, strengthening US leadership in electronics and photonics and enabling rapid translation of scientific discoveries into real-world applications. This research investigates 3D One-step Heterogeneous Manufacturing for Integrated Circuits (3D OHMIC), a custom-built additive manufacturing platform that integrates the high throughput of digital light processing with the sub-micron resolution of stereolithography and femtosecond-laser-based photoreduction to enable one-step fabrication of multi-scale metal–polymer structures. The research aims to establish the fundamental mechanisms of light-assisted metallization by examining photoinduced excitation, transport, and metal-ion reduction in photoreactive resin systems using time-resolved spectroscopy and controlled single-beam experiments, quantifying the roles of wavelength, intensity, and repetition rate in govern