The field of tissue engineering aims to fulfill the great clinical need to repair, replace, or regenerate impaired tissues and organs by delivery of a combination of cells, biomaterials, and biochemical and physicochemical factors. Indeed, tremendous strides have been achieved over the past several decades to construct implantable avascularized constructs such as skin, cornea, and bladder towards treatment for diseases and/or injuries. However, obtaining functional, physiologically relevant tissues is still a major challenge in the field due to the necessity of a vasculature system to supply nutrients and remove waste in thick constructs. This challenge can be attributed to convective transport limitations which results in necrotic cells due to inadequate access to nutrients. Indeed, vascularization of engineered thick tissue constructs is the current impediment in tissue engineering. Additionally, lack of the ability to recreate the heterogeneous patterns of cells and matrix to obtain constructs with controlled shape and architectures has further hindered progress towards organ replacement. This thesis aims to address these limitations by developing, characterizing, and validating a light-based 3D printing platform towards realization of thick, functional tissue constructs containing physiologically relevant micro-architectures. Of key importance towards achieving this goal, novel photopolymerizable formulations were identified and demonstrated towards stereolithographic generation of thick, perfusable hydrogels. Our hardware and materials innovations were then applied towards generation of hydrogels (composed of ≥90% water) containing various unprecedented space-filling, interpenetrating vessel networks, a hallmark of advanced multicellular life. We demonstrated a plethora of biological utility of our approach by illustrating examples of intervascular interstitial transport, generation of viable and functioning in vitro models of lung and bone tissue, and construction of a therapeutic transplantation liver model. This work unlocks transformative opportunities to mimic, interrogate, and utilize intricate multivariate vascular architectures that are vital to advanced multicellular life.