Diagonal tensile tests have been carried out on totally 28+37= 65, 755 mm x 755 mm square wall panels made of traditionally used low strength brittle bricks and recently produced high strength hollow block two holed bricks. Some of the wall panels are plastered and CFRP layers have been bonded on some of them with different application types, prior to tests. The results are presented in two groups of diagrams in terms of load-diagonal shortening and shear stress-shear angle. The nonlinear behavior of these brittle specimens has been obtained at the end, which can be utilized in nonlinear analysis. The results of six one story-one bay RC frames, infilled by the same materials used in shear panel tests, have been presented in the second part of the paper.