It is possible to define Green and Sustainable Chemistry (GSC) that should be the innovative chemical technology to aim at human-and-environmentally-friendly and sustainable development for the society, strongly considering the limited availability of resources and energy from the earth and the importance of its protection. “Human-and-environmentally-friendly” means that the influence to person's health and environment creature are little and a load to the global and/or local environment is also few. “Sustainable” implies sublime social concept that could satisfy current generation's demands, without depleting the resources that should be necessary for coming generations. In these meanings, we should image the ideal of coexistence and coprosperity among all the creatures on the earth. Though there are various subjects for the ideal, we could place GSC in the status of the solutions. GSC is a revolutionary approach through innovation and improvements explored through the entire life cycle of a given product in terms of, for example, product design, raw material choices, production processes, product applications, recycling, etc. GSC is a future-oriented concept for chemical technology applied to sustainable development that is designed to reduce environmental loading while simultaneously promoting economic efficiency. To promote GSC further, a suitable evaluation method to express the degrees of the improvements by GSC in a simple and easy way is absolutely essential. In this paper we propose i-Messe, impact Metrics for Environmental, Safety and Socio-Economic, that is versatile for various evaluations in the viewpoint of GSC and does not require a large amount of labor for evaluation. i-Messe is consists of three relative comparisons from the viewpoints of Environmental, Safety and Socio-Economic Impact respectively between an old technology and an improved one by GSC. In other words, the simple and easy technique adopting the general idea of life-cycle thinking is necessary for the GSC evaluation. Under such a background, we present i-Messe as a suitable method to evaluate and express the superiority of GSC technology intelligibly. We also introduce some case studies by i-Messe.