A new series of pyrene‐based, pure‐blue, fluorescent, stable monomers, namely 2,7‐di‐tert‐butyl‐4,5,9,10‐tetrakis(p‐R‐phenylethynyl)pyrenes, have been successfully synthesised by Pd/Cu‐catalysed Sonogashira coupling in excellent yield. The cruciform‐shaped, π‐conjugated structures were fully characterised by 1H/13C NMR and IR spectroscopy, mass spectrometry and elemental analysis. As revealed from single‐crystal X‐ray analysis, there is a herringbone pattern between stacked columns, but the π‐π stacking distance of adjacent pyrene units was not especially short at about 5.82 Å due to the introduction of the two bulky tBu groups in the pyrene rings at the 2‐ and 7‐positions. The photophysical properties of these monomers were carefully examined in different organic solvents, and these data strongly indicate their promising application as blue‐emitting materials in organic light‐emitting diodes (OLEDs).