Nowadays the rapid population growth in the world has highly aggravated the need for private houses and large infrastructure installations all over the world that tremendously needs the consumption of cement. However, the production of Cement is very high energy-intensive, environmentally unfriendly, and consumer of nonrenewable natural resources. Taking into account this universal issue, this study aims to investigate the partial replacement of cement with chickpea straw ash enhanced by natural silica sand powder (CSA-NSSP) in cement mortar production. In proceeding with the research, substantial experiments are carried out by partially replacing portland cement with CSA-NSSP at 0%, 5%, 10%, 15%, and 20%, by weight of cement as per the guideline of ASTM C 109 for 3,7,28 and 56 days of curing ages. In the study, experimental works such as physical tests for sand, slump flow, consistency, and fines of cement have been conducted. In addition to these, hardened mortar properties such as density, compressive strength, ultrasonic pulse velocity (UPV), durability (sulfate attack and water absorption) as well as microstructural properties (FT-IR, TGA, DTA) are well examined. After knowing the experimental test results, the mutual correlation and dependency of the outcomes are analyzed by using a simple and general linear model (MANOVA) with the help of IBM SPSS and Origin Pro 2024 software tools. The experimental test results showed workability of the mortar decreases with an increasing percentage of replacement due to the high surface area of chickpea straw ash (CSA) and natural silica sand powder (NSSP). As the test result indicates the mechanical properties and durability performance of the mortar are best enhanced at of 15% replacement level compared to the other mixes that exemplify the involvement of CSA-NSSP in mortar production undergoes pozzolanic activity bringing additional C-S-H gel. Also, FT-IR, TGA, and DTA test results of the study depicted the pozzolanic activity of CSA-NSSP attained more additional densified and polymerized C-S-H gel and improved thermal resistance against temperature effect at 15% replacement. Thus, it is recommended to practice the utilization of locally available agricultural wastes such as chickpea straw ash as a supplementary cementitious material in mortar production. Keywords: Chickpea straw ash, natural silica sand powder, fresh mortar properties, hardened mortar properties, microstructure, durability