Ionic liquids (ILs) are salts with melting points below 100oC and have remarkable and designerrnflexible physicochemical properties that offer distinctive performance advantages in a variety ofrnsynthetic, catalytic, and electrochemical applications. They are widely used as green alternativesrnto conventional environment polluting volatile organic solvents (VOCs) due to their negligiblernvapor pressure. However, their application in areas like catalysis is limited by the limited numberrnof cations on which the majority of ILs in common use is based and due to the low solubilities ofrnorganometallic compounds in these groups of ILs. Their green credentials are also being put intornquestion as the interest in ILs increases. Hence designing new ILs for a given application shouldrnalso be accompanied by improvements in the methodology of their preparation with respect torneconomics of preparation, environmental impact and cumulative energy demand (CED). In arncurrent work done in our laboratory, [CnPhen]X (X= Br-, PF6rn-, Tf2N-) ILs have been synthesizedrnfollowing a similar procedure to commonly used ILs and they exhibited good solubilities forrnphenanthroline and phenanthroline - metal complexes. Tetrafluoroborate ILs normally exhibitrnlow melting points and low coordinating abilities that are desired for catalytic reactions. For thisrnstudy, we have synthesized a range of new [CnPhen]BF4 ILs with varying alkyl chains. Evenrnthough, the new water miscible [CnPhen]BF4 ILs could be synthesized according to thernconventional procedure for the synthesis of other water miscible BF4rn- containing ILs, werndeveloped a new simple anion metathesis procedure, which has cut down reaction times,rnimproved yields and bypassed the difficult by-product separation and product purification steps.rn[CnPhen]BF4 ILs exhibited good solubilities for phenanthroline and a wide range ofrnphenanthroline based metal complexes. Their melting points were found to be relatively lowerrnthan its halides, PF6rn- and some of Tf2N- containing analogues and followed the same trend withrnalkyl chain length of the cation as its [CnPhen]Br precursor. Furthermore, these ILs are found tornbe soluble in a larger number of organic solvents than their analogous salts, which offerrnflexibility for application in a number of reaction and catalysis schemes.rnKEY WORDS: Ionic liquids, tetrafluoroborate, phenanthroline, phenanthrolinium ionicrnliquids, metal complex solubility, homogeneous catalysis