The rational breathers (Akhmediev, Kuznetsov-Ma, Peregrine) through the modulation instability (MI) are excited in positive ion- negative ion collisional plasmas by means of analytical and computation. The dynamics of the modulated waves are modeled by a nonlinear Schr & ouml;dinger type equation with a linear damping term that arises due to the ion-ion weak collision. Both the low and high frequency waves undergo MI in a certain parameter space (that depends on the mass and temperature of both the ions). The computation on the basis of experimental parameters reveal the formation of rational breathers on a finite background in PINI plasmas. The weak collisional dissipation delays the wave focusing process of the rational breathers and also enhance the amplitude of the second wave focusing in the Akhmediev breather dynamics.