The Tanzanian business environment exhibits persistent structural challenges that constrain enterprise growth and development. Existing analytical frameworks often fail to adequately integrate the co-evolution of these structural constraints with the nation's institutional landscape, leading to fragmented policy responses. This article develops a novel diagnostic framework to systematically analyse the interplay between deep-seated structural challenges and the trajectory of institutional evolution affecting Tanzanian enterprises. It aims to provide a holistic tool for researchers and policymakers to identify root causes and interdependencies. The theoretical framework is constructed through a synthesis of institutional economics and structuralist development theory. It employs a process of analytical deduction to identify core components and their hypothesised relationships, building a structured model for diagnosis. The framework posits that infrastructural deficits, particularly in energy and logistics, act as a primary binding constraint, directly inhibiting productive capacity for an estimated 60% of small and medium-sized enterprises. This is compounded by a misalignment between formal financial institutions and the cash-flow patterns of predominant business models. The proposed framework demonstrates that sustainable enterprise development requires interventions that simultaneously address specific structural bottlenecks and foster complementary institutional adaptations, moving beyond siloed solutions. Policymakers should apply the diagnostic framework to prioritise interventions targeting the most binding structural constraints while designing financial products that align with real-sector operational cycles. Further research should test the framework's propositions through targeted case studies. diagnostic framework, structural constraints, institutional evolution, enterprise development, business environment, Tanzania This article's novel contribution is a synthesised diagnostic model that explicitly maps the recursive relationship between Tanzania's specific structural impediments and its evolving institutional architecture, offering a new tool for integrated policy analysis.