We present a study of three B{sup 0} decay modes useful for time-dependent CP asymmetry measurements. From a sample of 9.7x10{sup 6} BB(bar sign) meson pairs collected with the CLEO detector, we have reconstructed B{sup 0}{yields}J/{psi}K{sub S}{sup 0}, B{sup 0}{yields}{chi}{sub c1}K{sub S}{sup 0}, and B{sup 0}{yields}J/{psi}{pi}{sup 0} decays. The latter two decay modes have been observed for the first time. We describe a K{sub S}{sup 0}{yields}{pi}{sup 0}{pi}{sup 0} detection technique and its application to the reconstruction of the decay B{sup 0}{yields}J/{psi}K{sub S}{sup 0}. Combining the results obtained using K{sub S}{sup 0}{yields}{pi}{sup +}{pi}{sup -} and K{sub S}{sup 0}{yields}{pi}{sup 0}{pi}{sup 0} decays, we determine B(B{sup 0}{yields}J/{psi}K{sup 0})=(9.5{+-}0.8{+-}0.6)x10{sup -4}, where the first uncertainty is statistical and the second one is systematic. We also obtain B(B{sup 0}{yields}{chi}{sub c1}K{sup 0})=(3.9{sub -1.3}{sup +1.9}{+-}0.4)x10{sup -4} and B(B{sup 0}{yields}J/{psi}{pi}{sup 0})=(2.5{sub -0.9}{sup +1.1}{+-}0.2)x10{sup -5}. (c) 2000 The American Physical Society.