The notion of Sustainable Development has rapidly gained considerable attention since the last
decades of the twentieth century. It has become a locus for global paradigm shift on environment and development issues particularly after Rio Conference in 1992. The comparative analysis of Agenda 21 and major UN documents, MDG, and RIO+20 as well as some major sources are made to provide a context for the assessment of landscape and environment importance for achieving sustainability. Study showed almost half of the Agenda 21 is devoted to the Environmental problems, landscape issues and protection of nature and natural resources. Landscape ecology and ecological complexity theories have been widely used in recent decades to analyze natural systems and artificial phenomena to predict the future behavior of systems; and to provide better solutions for balanced interactions of human and living organisms at larger scales. The paper investigated landscape ecology and complexity theory potentials for better understanding landscape system and its nature as an ever changing semi-living phenomenon, which plays a key role for the life of inhabitants of the planet. Using an integrated approach and analyses, this research is to develop the ecological dimensions of landscape as framework for the contribution of landscape ecology and ecological complexity towards achieving sustainable development. Analyses led the paper postulates the new dimensions: Transformation complexity and Accumulation complexity; and reveals Ecosystem complexity and Biocomplexity to expand the current dimensions of ecological complexity, with their effects on the landscape systems, environmental sustainability and hence sustainable development.