The photophysical behaviour of a single pyrene substituted calix[4]arene derivative (MPCX4) has been investigated, as a function of pH, using steady state fluorescence and timeresolved emission spectroscopic techniques. An interesting dimer emission band has been observed exclusively in the alkaline solution (pH > 8) which has been attributed to the hydrophobic and stacking interaction between the pyrene moieties of the adjacent MPCX4 molecule. The self-assembled MPCX4 is disrupted by the introduction of another calixarene based host, p-sulfonatocalix[6]arene (SCX6), which eventually leads to the 1:1 complex formation between MPCX4 and SCX6, which is further characterised by ¹HNMR, FT-IR and HR-MS techniques. This complexation between MPCX4 and SCX6 also leads to the modulation of the prototropic equilibrium of MPCX4.